'First Day' in the Bible

And the LORD spake unto Moses in the wilderness of Sinai, in the tabernacle of witness, the first day of the second month, and in the second year after they were come out of the land of Egypt, saying,

and gathered all the congregation together, the first day of the second month, and reckoned them after their birth and kindreds and houses of their fathers by name from twenty years and above, head by head;

He that offered his offering the first day, was Nahshon, the son of Amminadab, of the tribe of Judah.

Also, when ye be merry in your feast days and in the first days of your months, ye shall blow the trumpets over your burnt sacrifices and peaceofferings, that it may be a remembrance of you before your God. I am the LORD your God."

and all that the LORD hath commanded you by the hand of Moses, from the first day forward that the LORD commanded among your generation:

And in the first day of your months, ye shall offer a burnt offering unto the LORD: two young bullocks, and a ram, and seven lambs of a year old without spot,

The first day shall be a holy feast, so that ye shall do no manner of laborious work therein.

Also, the first day of the seventh month shall be a holy feast unto you, and ye shall do no laborious work therein. It shall be a day of trumpet blowing unto you.

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