I have read about a first Seder and a second Seder. One source said this was because of the number of lambs that had to be sacrificed. Was 15 Nisan (1st day of Unleavened Bread) a High Sabbath?
The reference to the first and second Seder is to be found in the Bible at:
Num 9:3 In the fourteenth day of this month, at even, ye shall keep it in his appointed season: according to all the rites of it, and according to all the ceremonies thereof, shall ye keep it.
Num 9:4 And Moses spake unto the children of Israel, that they should keep the Passover.
Num 9:5 And they kept the Passover on the fourteenth day of the first month at even in the wilderness of Sinai: according to all that the LORD commanded Moses, so did the children of Israel.
The Reason for the Second Passover
Num 9:6 And there were certain men, who were defiled by the dead body of a man, that they could not keep the Passover on that day: and they came before Moses and before Aaron on that day:
Num 9:7 And those men said unto him, We are defiled by the dead body of a man: wherefore are we kept back, that we may not offer an offering of the LORD in his appointed season among the children of Israel?
Num 9:8 And Moses said unto them, Stand still, and I will hear what the LORD will command concerning you.
Num 9:9 And the LORD spake unto Moses, saying,
Num 9:10 Speak unto the children of Israel, saying, If any man of you or of your posterity shall be unclean by reason of a dead body, or be in a journey afar off, yet he shall keep the Passover unto the LORD.
Num 9:11 The fourteenth day of the second month at even they shall keep it, and eat it with unleavened bread and bitter herbs.
Another source said that at the time of Christ the first Seder was the day before the second or regular Passover Seder.
Where can I find out more in old Jewish sources (e.g., Mishnah, Talmud, Josephus) about this practice? Monte
Prior Verse 2 in this section stresses the necessity of observing this festival at its G-d appointed time, even under circumstances that might seem to require its postponement, therefore the Pesach offering is brought on the 14th of Nissan even if the day falls on a Sabbath. A rabbinical dispute arose over this question of celebrating Passover on the Sabbath just before Yahshua’s event and Hillel Ha Nasi (Hillel the Prince) ruled that Passover took precedence over the Sabbath and could be celebrated on Shabbat. Pesach sheni is the second Pasach, G-d ordained for people who were ineligible to bring the Pasach offering because of contamination (touching human corpses). This second Pesach would be brought a month after the appointed time of the first Pesach. The second Pesach differs from the first in that there is no festival associated with it, even for the bringing of an offering. Futhermore, although they may not eat leavened food (chametz) with the offering (v. 11) they may possess and eat chametz on the day they bring it. (RashiL Pesachim 95a) The Talmud has two versions of how those referred to in this scripture became contaminated, either they were the bearers of the coffin of Joseph, who had asked his brothers to bury him in the Land of Israel or they came upon an unattended, unidentified corpse and had fulfilled the commandment of burying it (Succah 25a). Either way they became ineligible of bringing the Pesach offering and since they were engaged in doing a Mitzvah they should not be deprived of participating in the spiritual blessing of Pesach. Since the contamination was not their fault, but required of them. They felt they should be allowed to participate in the Pesach offering (Or HaChaim). There are parallels to Yahshua’s own Halacha here as seen when He addresses the Pharisees and Scribes on doing a mitzvot on Shabbat. He employs the accepted rabbinical interpretation of kal v’ chomer (light and heavy) corresponding to what philosophers call a fortiori (with even greater strength). Moshe said to them, “stand still and I will hear” and consulted YHVH and he received the commandment of the second Pesach.
Was 15 Nisan (1st day of Unleavened Bread) a High Sabbath?
The High Sabbath or Shabbat Ha Gadol is the Sabbath that falls immediately before Pesach.