The passages translated ‘first day of the week’ in the four Evangelists, Acts, and 1Corinthians, are traditional mistranslations whose design is to suppress the fact that the resurrection of Yeshua (Jesus) was on the seventh day Sabbath. Anyone who can read Greek knows that they say, ‘one day of the Sabbaths’ (μιᾷ τῶν σαββάτων). But since the Greek was used by Jews, we have to consider the use of a Hebrew idiom in their usage which does not exactly correspond to the meanings usages or grammar of Greek used in the rest of the Greek world.
It is pretty obvious that the word ‘one’, μιᾷ in Greek is being used like the Hebrew word for ‘one’ to mean ‘first’ . In Gen. 1:5, the word אֶחָד is used in this fashion to mean ‘first’ day. For this reason the resurrection day idiom means ‘first of the Sabbaths’ as rendered in Young’s Literal Translation (YLT: John 20:1, 19; Luke 24:1; Mark 16:2; Mat. 28:1).
The word אֶחָד echad also has a feminine form achat: אַחַת. The feminine form corresponds exactly to the Greek mia μιᾷ, which is the feminine form for ‘one’ in Greek. (Both languages have masculine and feminine forms for the word ‘one’).  The Greek phrase ‘of the’ ton, τῶν, is what is called genitive. The genitive is translated with the word ‘of’; In Hebrew this is expressed with a form called construct in the form ‘a of the b’, where a and b are two nouns.’ For example in 1Samuel 2:36, the Hebrew אַחַת הַכְּהֻנּוֹת, achat ha-kehunnot, means ‘one of the priesthoods.’ In the Greek version (LXX) this looks like: μίαν τῶν ἱερατειῶν. 
The final words in our phrase are τῶν σαββάτων. Nehemiah 10:34 shows what this looks like in Hebrew ha-shabbatot: הַשַּׁבָּתוֹת. The Greek version (LXX) matches this with τῶν σαββάτων. The word for Sabbath is properly feminine in gender. This is shown by the fact that its plural form is formed with the Hebrew ot וֹת, which is the means of making a feminine word plural. 
Therefore to reconstruct the Hebrew idiom behind the Hebraism in the Greek μιᾷ τῶν σαββάτων, requires: אַחַת הַשַּׁבָּתוֹת. In the Greek idiom σαββάτων is treated as a feminine word by way of the Hebrew idiom (compare 1Sam. 2:36). We therefore don’t expect this idiom to act like regular Greek.
Regular Greek treats σαββάτων as a neuter even though the -ων ending may stand for feminine (cf. 1Sam. 2:36). But the question may be considered from the point of view of regular Greek. In regular Greek if the gender of a head adjective differs from a following genitive, then an implied noun of the same gender needs to be supplied after the adjective. In this case ‘first of the Sabbaths’ implies ‘first day of the Sabbaths,’ which can be expanded in Greek: μιᾷ ἡμέρᾳ τῶν σαββάτων. Once expanded like this, it is obvious to anyone who knows Greek that ἡμέρᾳ τῶν σαββάτων is the ordinary phrase for ‘the Sabbath day.’ 
The same sort of usage is seen in counting the days of unleavened bread. One may refer to any particular day of the feast as ‘a day of unleavens’ (which in NT times included the ‘head day’ of the feast).  For example Luke says, ‘came the day of unleavens on which it was necessary to sacrifice the Passover’ (Luke 22:7). Here ‘day of unleavens’ refers to any day in the feast (ἡμέρα τῶν ἀζύμων), but it is further defined by ‘on which it was necessary to sacrifice the Passover.’ Mark 14:12 defines the same day as ‘the firstmost day of the unleavens’ (τῇ πρώτῃ ἡμέρᾳ τῶν ἀζύμων), where ‘firstmost’ is an ancient Hebraism from Exo. 12:15. The point is that ἡμέρᾳ τῶν ἀζύμων is parallel to ἡμέρᾳ τῶν σαββάτων. The later phrase means any seventh day Sabbath in general, just as ἡμέρᾳ τῶν ἀζύμων means any one of the various days of unleavened bread in general. This is the case until it gets modified by an adjective or other descriptive phrase specifying a particular day of the Sabbaths or a particular day of the unleavens.
For example, Josephus specifies the second day of unleavened bread as: δευτέρᾳ τῶν ἀζύμων ἡμέρᾳ, ‘second of the unleavens day’ (literally); or put in proper English order ‘second day of unleavens.’  Josephus could well have left the word ἡμέρᾳ out, ‘second of unleavens’ or he could have inserted it after the number, ‘δευτέρᾳ ἡμέρᾳ τῶν ἀζύμων’. Therefore μιᾷ ἡμέρᾳ τῶν σαββάτων or μιᾷ τῶν σαββάτων ἡμέρᾳ is simply counting a particular Sabbath, exactly the same way a particular day of unleavened bread is counted.
Matthew says ‘firstmost of the unleavens’ (πρώτῃ τῶν ἀζύμων), leaving the word ‘day’ out, and Mark includes it, ‘firstmost day of the unleavens’ (πρώτῃ ἡμέρᾳ τῶν ἀζύμων). In all cases ἡμέρᾳ τῶν ἀζύμων means some day of the feast. In all cases ἡμέρᾳ τῶν σαββάτων means some Sabbath. The word ‘firstmost’ (πρώτῃ) or ‘first’ (μιᾷ) only tells us which particular one.
The existence of a ‘first of the Sabbaths’ is taught by Lev. 23:15 where there are instructions to count seven Sabbaths after the first annual Sabbath for Passover.  To follow this commandment requires counting a first Sabbath. So the significance of the first of the Sabbaths is readily explained.
To be sure there is an enormous degree of religious opposition to these points, because the Church has a tradition to defend. The Jews rejected Messiah because of their traditions on who could be the Messiah and who could not be the Messiah. If tradition deceived the Jews, then tradition can deceive anyone. The Church has a tradition that the Torah was abolished. For this reason, the Church married itself to Sunday, in order to divorce the Sabbath.
If any so called scholar says that my points here cannot be possibly true because Greek or Hebrew language rules prevent it from being true, then rest assured that they are either outright liars or they are simply incompetent teachers who have not thought it through on the basis of objective linguistic science. I hope that anyone arguing otherwise falls into the last category, but the fact is that incompetence is just as damaging as someone who knowingly teaches a fraud. I mean teachers who say that a Sabbath resurrection isn’t possible, and not teachers who admit that it is possible, who nevertheless choose to believe otherwise.
With that said, these traditionalist Church scholars claim that ‘first of the Sabbaths’ (μιᾷ τῶν σαββάτων) is properly rendered by the Hebrew phrase: בְּאֶחָד בַּשַּׁבָּת be-echad ba-shabbat, ‘on one in the Sabbath’, where they interpret the word ‘Sabbath’ to mean ‘week.’ This is indeed an idiom in the Mishnah and Seder Olam. But it is a late idiom coming after about AD 140 or 150. There is no usage like this contemporary with the Evangelists, prior to AD 90. There is but a singular instance in Luke 18:12 where it has been claimed that σαββάτου means week, yet with two meals a day and fasting practices among Jews, it cannot be held for a certain that this one usage is sufficient to establish a meaning of ‘week,’ which even if it may be supposed, does not mean that such a sense should be transported to the resurrection contexts.
Likewise, there is no proof that the Seder Olam or Mishnah usages should be transported to the resurrection passages. The existence of the usage some 100 years after the resurrection does not prove that the resurrection passages used that sense. Some may bring up the Syriac usages, but these are even later than the one’s just mentioned.
I will now point out the lack of correspondence between בְּאֶחָד בַּשַּׁבָּת and μιᾷ τῶν σαββάτων. The first point is that the Greek employs no word ‘in.’ The Greek could have, and would have rendered this Hebrew idiom as, ‘μιᾷ ἐν τῷ σαββάτῳ.’ No one knows why the Jews invented בְּאֶחָד בַּשַּׁבָּת about AD 150. However, I suspect that some Rabbis were just as eager to be rid of ‘first of the Sabbaths’ in connection to Messiah’s resurrection as the Gnostic Church at the time was.  I believe that the best explanation is that the rebellious house of Judah conspired with the rebellious house of Israel. ‘The princes of Judah have become like those who move a boundary’ (Hos. 5:10). In this case, the moved boundary is adding בְּאֶחָד בַּשַּׁבָּת to post Second Revolt Hebrew, and more particularly the claim that it represents the resurrection day.
We don’t have to rely just on the one phrase used in the resurrection passages to know that Messiah was raised on the Sabbath. I have worked out all of biblical chronology to show that this was the case, and have exposed a whole network of presupposed deceptions that serve tradition and not the truth. This is just one of many articles I write on this subject. All it takes is someone faithful to personal intellectual integrity, to approach the subject with as objective scientific inquiry as they can combined with a prayer of humility to find the truth. I know there are some faithful out there who have this kind of integrity amid all the gnostic Christians who think they are saved by ‘believe only’, and who do not regard intellectual honesty as a necessary virtue. I urge all honest investigators not to rely on those nominal Christians who do not know the good news, or on the Rabbis who don’t want to know it either.
1. ^ source: torahtimes.org\articles\hebrew_idiom.html. Original content article by Daniel Gregg. All Rights Reserved. Permission granted to cite or copy article with proper attribution, i.e. include this paragraph with article or portion thereof that is quoted as the reference footnote. If used on a forum, group, this requirement is only needed for any opening post to start a discussion or if the article is brought in to another discussion to address issues raised in another discussion.
2. ^ The ordinary Greek word for 'first' is: πρῶτός. The difference is that 'one' is a cardinal number whereas 'first' is an ordinal number.
3. ^ Greek has three forms, feminine: μία , masculine: εἷς, and neuter: ἓν .
4. ^ The form μίαν appears here and in Matthew 28:1 because it is governed by an accusative preposition εἰς, i.e. εἰς μίαν σαββάτων and ἐπὶ, i.e. ἐπὶ μίαν τῶν ἱερατειῶν (1Sam. 2:36). The other usages of μιᾷ, i.e. John 20:1: Τῇ δὲ μιᾷ τῶν σαββάτων, are governed by the dative. The difference is between 'into the first of the sabbaths,' and 'on the first of the sabbaths.'
5. ^ The Hebrew lexicon lists shabbat as a feminine and masculine noun. The latter gender is due to the influence of the masculine word yom in Hebrew on shabbat. The feminine plural form shabbatot shows that the word is properly feminine.
6. ^ The phrase appears in the LXX and NT at Exod. 35:3; Lev. 24:8; Num. 15:32f; Num. 28:9; 1 Ma. 2:32,41; 1 Ma. 9:34,43; Isa. 58:13; Jer. 17:21f,24,27; Ezek. 46:1,4,12; Lk. 4:16; Jn. 20:19; Acts 13:14; Acts 16:13; See also LXX: Exod. 20:8; Deut. 5:12,15; 1 Ma. 2:34; 2 Ma. 15:3; Jer. 17:22,24,27; Similar usage in: Ant. 12:274; Ant. 7:305; Ant. 12:259,274; Ant. 13:12; Ant. 14:264; Ant. 18:354; Neh. 10:32; Neh. 13:15,19; Lk. 13:14,16; Lk. 14:5; Jn. 19:31; This usage is so fixed that it cannot mean 'day of the week', 'day from the sabbath', 'day after the Sabbath', or any similar corruption. It must mean 'day of the Sabbaths,' or 'the Sabbaths day'.
7. ^ Explaining this would take a whole additional paper. Briefly, Exodus 12:15 calls the 14th of Nisan: בַּיּוֹם הָרִאשׁוֹן, which is a very archaic Hebrew (using an Aramaic intensive ending) for saying headmost or firstmost. Some even say that the Greek word πρῶτός can be used in a superlative sense, i.e. firstest, or first most.
8. ^ Josephus Ant. 3:250. This is the famous passage where Josephus says the sheaf was waved on the second day of the feast, i.e. Nisan 16.
9. ^ “And ye shall have counted for yourselves, in the day after the [annual] Sabbath, from the day ye brought in the sheaf of the wave offering, seven Sabbaths shall be completed” (Lev. 23:15). As noted by Josephus, this sheaf was waved on the 16th of Nisan, which is the day after the annual Sabbath. Subsequently, seven Sabbaths were counted in the 49 days following Passover. In the time after the seventh Sabbath a 50th day was counted for Shavuot. The details for this and the exegesis of this text are in another paper of mine.
10. ^ Christianity went through a major apostacy in the early second century, and one of the famous heretical leaders was Marcion. Marcion rejected the Torah and the Prophets, renaming it the Old Testament. He renamed the Apostolic Writings the New Testament, and considered only the Gospel of Luke, Acts, and the writings of Paul as Canon, and this after editing them to conform to his gnostic beliefs. A majority of Christians were swept away in this apostacy. Before this the Mosaic covenant was refered to as the ancient covenant or the brit olam, the everlasting covenant, and the new covenant was its renewal. The terms did not refer to collections of writings, one set invalid, and the other presumably valid. But Marcion's heresy was widespread enough to cause a change in Christian usage and to cause the canon to be categorized as Old Testament and New Testament.
Gnostics generally rejected the Creator of Israel, because they considered the creator of matter evil. Their father god was said to be a god above the Creator, and the Creator they equated with a devil or a demon. Gnosticism of this form was so outrageous that eventually Christians backed away from it, but not before it left a legacy in the Church that is present to this day. During the heyday of the Gnostics, true Christians were few, or greatly outnumbered. Christianity has now evolved into a situation where most Christians are nomimal and their Christianity consists of traditions, some reflecting Scripture, and other traditions reflecting the influence of the Gnostics.
Later on the Gnostic Churches began to get some sense into their apologetic and realized that rejecting the OT as canon was not a good idea. They therefore brought it back into the canon. It was during this period of time that anti-law interpretations of Paul evolved, and that Sabbath was changed into Sunday.