'First Day' in the Bible

And Jehovah spake unto Moses in the wilderness of Sinai, in the tent of meeting, on the first day of the second month, in the second year after they were come out of the land of Egypt, saying,

And they assembled all the congregation together on the first day of the second month; and they declared their pedigrees after their families, by their fathers houses, according to the number of the names, from twenty years old and upward, by their polls.

And he that offered his oblation the first day was Nahshon the son of Amminadab, of the tribe of Judah:

In the first day shall be a holy convocation: ye shall do no servile work;

And in the seventh month, on the first day of the month, ye shall have a holy convocation; ye shall do no servile work: it is a day of blowing of trumpets unto you.

And Aaron the priest went up into mount Hor at the commandment of Jehovah, and died there, in the fortieth year after the children of Israel were come out of the land of Egypt, in the fifth month, on the first day of the month.