12:2a ראשון also means "chief", which is to say, the most important, on account of the Passover and Exodus.  This new moon is also the first in number, and is called Aviv (cf. Deut. 16:1).  Note carefully that this new moon is the "first of months" and "head of months".  It does not say that the first new moon defines the beginning of the year, as some mistakenly think.  The first day of Aviv is not the new year day.  It is simply the first day of the first month of the months of the year.  The construct relation "of the year" presupposes a prior definition of the year, which is marked by the circuit of the sun (cf. Gen. 1:14), a time called the "turn of the year" (1Sam. 1:20), and measured by the number of days in a year (cf. Exodus 13:10).  The "turn of the year" is a technical phrase for the day in which days cease to be shorter than nights, and begin to grow longer than the night again.   This day is universally known as the Spring Equinox, and was specially marked by all advanced ancient cultures.   Since the new moons do not synchronize with the spring equinox, the definition of the "head of months" has to be based on the idea of a equal or greater part of the month actually being in the new year.  Put another way, the days in the new year must be equal to or greater than the days of the month straddling the old year.    Equivalently, the 15th of Aviv must fall on or after the spring equinox.   If the 15th of the month does not fall on or after the equinox, then that month is counted in the old year, and is not the "head of months" of the new year.  This is reinforced by the fact that three feasts are to be kept in a year (Exodus 23:17).  Hence Passover must be in the new year, even if the days of the month before it are in the old year.  This will prevent some years from having two feasts, and others four.

An alternative method of determining the first of the months comes from ancient Babylon.  It states that the first month is that month in which all of its days are in the new year.  This rule is contradicted by several commandments.  1. Israel was not to delay its first fruits (Exodus 22:29), and Israel was not to eat new grain until the day after Passover (Lev. 23:14).   As the new grain often ripens in a month prior to the Babylonian rule, following the Babylonian rule would cause both delay and hardship for those wanting to obey the commandments. 2. Also, the biblical chronology contradicts the Babylonian rule in that the birth of Messiah is not placed according to it, nor is His death and resurrection.   The death of Messiah was on March 24, AD 34, corresponding to Wednesday, Aviv 14.  This corresponds to the first rule stated above, and not the Babylonian rule.

It is taught in error by the Karaites that the only determining criteria for the first month is the observation of ripe barley before the Passover.  This error is dealt with in the notes on Deuteronomy 16:1.

12:2b The words are החדש הזה.  It means both "this new moon" and "this month".  American Indian cultures would often measure time in "moons" using the word in a way that did not specialize a vocabulary distinction between "month", and "moon".  Similarly, Hebrew does not distinguish between "new moon" and "month", leaving it to the context to determine the exact shade of meaning.  The "new moon" is a semi-holiday in the Scripture, and it is likely that Yahweh spoke to Moses on the new moon day for the first day of Aviv.

The new moon was the first visible crescent of the moon returning from its dark phase.  It would be seen as a thin sliver in the west shortly after sunset.  This definition is the ancient sense of the word that was common in ancient cultures, Assyria, Babylonia, Persia, and Greece.  The Romans, and their Roman definition of "month" without respect to the cycle of the moon was a late barbaric, and relatively modern innovation, and the Romans showed their calendar incompetence by miscalculating the length of the year so that Julius Caesar had to repair it, and yet this was not enough, because a Roman Catholic Pope had to further repair it in 1582.  This Roman bumbling was the result of neglecting actual observation as a check and correction on their perpetual calendar.  They did not observe the day of the new crescent like ancient cultures before them, nor did they pay attention to the actual time of the equinoxes.  Accordingly, things drifted out of synch with the celestial reality after a time.

The Egyptian calendar deviated from those of Mesopotamia, where Abraham had his original home in Ur of the Chaldees. The only thing that Israel learned from the Egyptian calendar was to reckon the working day, and days for sacrificial offerings on a sunrise basis.  Later Sabbath's and holy days were reckoned as in the fertile crescent, on a sunset basis.   Israel would see the new moon in the evening, after sunset, and would reckon the "new moon" semi-holiday on a sunset basis, but the working day and Temple day would be counted from sunrise the following morning unto the next morning after that.

According to Jewish historical sources in the Mishnah, the new moon was observed by posting witnesses that would report their sightings of the first crescent to a calendar council in Jerusalem.  So during the time of Yeshua, the ancient method, approved in the Scripture, was used by Judea.  The practice of calling the dark moon "the new moon" is a relatively late and modern change of terminology originating from astronomers who found it easier to calculate the conjunction of the moon than the crescent moon.  The methods for calculating the crescent moon were not fully developed or competent until Sir Isaac Newton applied calculus to the problem of gravitation.  But the astronomer's foible of referring to the dark moon as the "new moon" had stuck before that.

If anyone has any doubt about the meaning and definition of the "new moon", it is made plain by Yeshua's death and resurrection, which is what the Passover is all about.  The crucifixion date of Aviv 14, and this corresponds to the "new moon" definition as the first crescent for the year AD 34.  It should also be noted that Sir Isaac Newton settled on this year for the crucifixion, and so also the Jewish chronological scholar Solomon Zeitlin.  The facts, and chronological notations in the gospels only make sense when "new moon" is defined as the first crescent.   Biblical chronology is a finely tuned system of historical fact that is interdependent.  If one major benchmark is miscalculated, then the whole system is disharmonious.  When everything is set right, then all the details synchronize.  They line up like a coded lock.  Then the lock opens, and one knows that they have the correct solution.  

The importance of this cannot be stressed enough.  It is the failure to pay attention to detail and Scripture interpreting Scripture that has led the Church and Israel astray.  One statement, or one text can be easily misinterpreted or taken out of context.  To interpret texts in harmony takes much meditation and thought, and since Satan is always willing to encourage misinterpretation, it takes a double amount of double checking to make sure one is not deceived by some assumption he has introduced to change the meaning of what the Almighty really did say.

Since Yeshua is the Messiah, and he did die on the 4th day of the week, and did rise on the Sabbath, and since Daniel 9 and other chronological details are only harmonious as a total system when the "new moon" is properly defined and observed, then it stands to reason that changing the definition, or observing the times and seasons by another definition, would serve to undermine the historicity of Messiah's death and resurrection, which would harm the good news.  To employ this other definition in one's observances  is to become an anti-witness against Messiah.

Now surely the Jewish people are not aware of these consequences as a whole, nor Torah observant Christians.  But Jews have been led against Messiah, and against truths that witness to Him, and Christians have let themselves be led astray against Yahweh's Torah, and against his times and seasons, provoking Him to mighty anger by letting "Easter" be heard on their lips as if Yeshua invented it and approved of it.  As is well known, this term "Easter" comes from a pagan fertility goddess. 

Here is a little parable you can tell your friends.  A man had a wife named Ester.  Now this Ester was an adulteress, who murdered her children to conceal the fact that she was a harlot.  The man had a childhood girlfriend who was concerned for him, and exposed the evil deeds of his wife.  The man divorced Ester, and a few years later realized the girlfriend really loved him, and so he married her.   Now the man had a habit of many years with Ester, and so by and by he forgot the anniversary of his new wife, and called his new wife to a candlelit dinner on the anniversary date of his old wife.  And further, while at dinner, he forgot himself and said to his new wife "Dear Ester", I have a gift for you, and further forgetting himself gave his new wife a bunch of beautifully decorated eggs, because that was how he remembered his old wife used to celebrate her promiscuity, as the eggs represented her fertility.  (Note: Ester is how William Tyndale spelled Easter the 23 times he used it in his 1534 New Testament).

12:6a The Hebrew literally says, "between the settings" (בין הערבים).  The first setting point is noon, when the sun begins to go down, and the second setting point is sunset.  Between these two critical points of time is called "between the settings".   The proper time to slay the Passover lambs is the mid-afternoon of the 14th of Aviv.   Yeshua is the lamb of the Almighty (John 1:36), Messiah, our Passover (1Cor 5:7), was slain in the mid-afternoon on the 14th of Aviv (John 19:14; Matthew 27:45).  The hours are measured from sunrise, so the 6th hour is noon, and the 9th hour is 3 p.m.  Yeshua died at the 9th hour, which is exactly "between the settings", when the Passover lambs were to die.

If your bible translation says "twilight", instead of "afternoon" or "between the settings", then do not believe it!  Satan has managed to get many of his corruptions into the written word, and "twilight" is one one them.   The effect of this corruption is to spoil the chronological connection between Yeshua as the lamb of the Almighty, and the Passover lamb.

The mistranslation "twilight" is a heretical Karaite Jewish or Samaritan position.  It causes them argue for the slaying of the Passover lamb at the wrong time, after sunset during the twilight at the end of the 14th day of Aviv.  Christian's were deceived and fooled by this errant position, including many Christians trying to follow the Torah.   There is a good proof that "between the settings" means afternoon.  We are told in Exodus 30:8 that the time of the incense was "between the settings";  we further learn in Luke 1:10 that the hour of payer was the hour of incense, and finally, Acts 3:1 we are told that the hour of prayer was the 9th hour (3 p.m.).

12:8a "that night" is the night following the day part of the 14th of Aviv.  The scripture uses several definitions of day, and two definitions of a calendar day.  For the purposes of sacrifice the calendar day was sunrise to sunrise, as illustrated by Lev. 7:15.  For the keeping of  rest days, the calendar day was from sunset to sunset. When in Egypt, Israel became used to a civil day that began with sunrise, as this is what they did in Egypt.  So the 14th of Aviv is counted from sunrise beginning the day of Aviv 14 till sunrise beginning the day of Aviv 15.   With this in mind, "that night" meant the night following the day part of the 14th of Aviv.   The Passover lamb is eaten after sunset when the day part of the 14th of Aviv ends, however for the purposes of eating the Passover lamb, "that night" is reckoned as the "on the day of his offering" Lev. 7:15 until the morning.

12:10a The morning marks the end of the 14th of Aviv with respect to a sunrise reckoning.   Lev. 7:15 prescribes the morning as the limit of time for the sacrifice to be eaten on the day of its offering.  The default or common reckoning of a "day" in the Scripture is daybreak to daybreak.  See Genesis 1:5 note.

12:15a Almost every translation of this passage is badly translated, so as to imply that leaven is actually removed on the first day of unleavened bread. Some might be tempted to solve the problem by claiming that הראשון means the previous day, but this opinion is refuted by the second use of the same word at the end of verse, "from the first day until the seventh day", where clearly "first" means the 15th of Aviv.   The key to this text is the verb שבת, which is the root of "Sabbath" and means  to "cease" or "rest".  The "leaven" does not "cease" or "rest" until it has been removed.  Only then is the leaven in a state of resting from the house.   So to cause a state of Sabbathing for the leaven on the first day, requires one to be rid of it before the first day begins.  Then the leaven is taking a Sabbatical.   One of the main reasons the first day of unleavened bread is called השבת in Lev. 23:11, because that day begins the Sabbath of leaven.  The other reason, is because it is actually a rest day (Lev. 23:7).