Their error is their teaching that the new moon is on the day of the conjunction instead of the day of sighting. Biblically, the new moon signals the day starting the month by showing its light. It is therefore to be the day of sighting. Genesis 1:14 says that the Almighty created the lights to be signs. And the moon is the lesser light. The moon is obviously the sign to begin the month. Yahweh tells us very clearly to use the moon's light as the sign:
Then the Almĩghty says, “Let there be lights in the vault of the heavens to separate the day from the night, and let them be for signs, even for appointed times and for days and years;
The "lights" are the signs. It is very important to heed the meaning of this word "Light." The Scripture is accurate in every detail. It says "let THEM be for signs." It says let what? THEM. "Them" refers to the lights. It does not say moon or sun. It says lights. Now of course the moon is a light only when it is lighted and can bee seen. Dark moons or conjunctions are not signs that are lights since nobody can see the moon when it is in conjunction. So a conjunction cannot give the sign (or signal) to start a month. One may calculate the conjunction, but it still would not be biblical to start the month with the conjuciton.
Also in all the ancient historical accounts, the new month was begun according to the sighting of the first lighted crescent. This is true in Josephus, Philo, all Jewish sources, and all ancient cultures except Rome and Egypt. Egypt used the last light of the old moon, and Rome's months had nothing to do with the moon's cycles. But in Assyria, Babylon, Persia, Greece, and other places where the Jews were compeled to follow the civil calendar, the new moon was according to the crescent.
The conjunction method is really a Rabbinic one introduced after AD 359 well after the destruction of the Temple in AD 70. It is completely unknown in Israel and the ancient world before that time.
So
how does 119 ministries persuade people that sighting the new moon is the
wrong way to start the month? The answer is that they have been deceived
by the tradition that a day always begins with sunset. In fact only
Sabbaths begin with sunset. All other days begin with the daybreak and end
with the daybreak. This is attested by by major scholarly works such as TWOT
(Theological Wordbook of the Old Testament), and BDB (Brown-Driver-Briggs
Lexicon), and Franz Delitszch, Jacob Milgrom, and other famous scholars. The
reason these scholars declare the tradition wrong is because it is wrong,
and in their scholarly work with the Hebrew texts, they have discovered it
cannot be supported.
I will leave the proof of the daybreak to daybreak day to my published book, "The Resurrection Day of Messiah Yeshua", which is available with preview pages on my home page. And meanwhile we will proceed to the texts which 119 Ministries thinks prove its erring teaching. The first of these texts is 1 Samuel 20:5, where David says "Behold, tomorrow is the new moon"; 119 Ministries argues that the only way David could know the next day was the new moon is if someone had calculated the conjunction, and then had told him about it in advance. But there is an alternative explanation. David saw the moon after dark. Here is proof that is possible. David's wife said to him, "If you do not save your life tonight, tomorrow you will be put to death" (1Sam. 19:11). So we see that in the night the next day is called "tomorrow." This is clearly the night before the day. So, it could have been at night that David said "tomorrow the new moon." What David means is that the new moon day with the feast on it is "tomorrow". He knew this because it was night, and he had just seen the moon after sunset.
Clearly, David's wife thought of the coming daybreak as "tomorrow." And it was at night. So too, in the night that David saw the new moon, he still regarded the daybreak as the next day. So the new moon day is marked #1 in the chart below, when David was first supposed to sit down with king Saul. Saul missed him and thought he might be "unclean"; On the second day of the feast, #2, Saul missed him, and Jonathan gave David's excuse, that he had gone to Bethlehem. Saul then tried to spear Jonathan in his anger. The next day is the third day when David and Jonathan meet at dusk.
So the basic problem is that 119 Ministries is trying to interpret the Scripture using a modern traditon, that has only been the tradition since AD 70. But there is more to this story. This calendar error has been widely spread by the heretical teacher Andrew Roth on pages 1019-1021 of his AENT. His other two heresies are as bad, if not worse than this calendar heresy. And I will mention them in a bit because they do have a bearing of the credibility of this theory. Roth's argument is based on 1 Samuel 20:5, the assumption that the crescent could not be calculated, the assumption that the conjuction could be calculated, the assumption that the coming daybreak could not be called "tomorrow" when it was already the "night" before it, and finally the assumption that ancient Israelites thought of the day as from sunset to sunset as a matter of couse. All these assumptions are either questionable or false. And the most critial assumption is proved false by the words of David's wife. There are other proof that the day then was daybreak to daybreak, which can be found in my published book, "The Resurrection Day of Messiah Yeshua", which is available with preview pages on my home page.
Now should we overturn the clear teaching of Genesis 1:14 and the historical record of how the new month was started for a faulty interpretation of 1 Samuel 20:6? Clearly no. So then, why about the credibility of the main teacher? Andrew Roth teaches that the original New Testament was written in Aramaic, and he also treats Aramaic as the language of Messiah's revelation disfavoring Hebrew. This teaching is also the teaching of the Aramaic speaking Church of the East. This theory has been disproven by many scholars who know both Aramaic and Greek. The Aramaic Peshitta was translated from Greek. There can be no doubt about it. The Aramaic text is full of Greek loan words from the Greek texts including words like 'nomos' instead of Torah, and "evangel" instead of the Hebrew "B'sorah". Further even the Greek conjunction 'de' is reproduced in the Peshitta 100's of times as the word 'din.' I have a book availabe debunking this theory in detail, including the claim to Aramaic Primacy. And it is an extremely dangerous and heretical theory, because it causes people to distrust the Greek texts which are the real original sources. It is nothing less than an attack on the texts delivered to the Saints.
Finally, mention should be made of Roth's worst heresy. It is the Nestorian Heresy of the Church of the East, and it appears on page 1052 of his AENT (Aramaic English New Testament). Here he denies the deity of Yeshua, saying, "The Spirit of YHWH, also known as the Ruach haKodesh, is both within Mashiyach and is YHWH; however, the nephesh (soul) of Y'shua is "the person" or vessel of Y'shua where the Spirit of YHWH dwells. The physical body of Y'shua and his soul are not YHWH, but Y'shua made himself subject ot YHWH in all aspects." Roth's heresy grows Gnostic on the next page (1053), "but, in reality there is no such thing as time with YHWH so you are part of I AM. Your existence came about from outside of time, in the mind of YHWH; therefore, in a spiritual or metaphysical way, you "existed" before you were born."