'First Day' in the Bible

In the first day ye shall have an holy convocation: ye shall do no servile work therein.

Speak unto the children of Israel, saying, In the seventh month, on the first day of the month, shall be a solemn rest unto you, a memorial of blowing of trumpets, a holy convocation.

On the first day shall be an holy convocation: ye shall do no servile work therein.

Also in the fifteenth day of the seventh month, when ye have gathered in the fruit of the land, ye shall keep a feast unto the LORD seven days: on the first day shall be a sabbath, and on the eighth day shall be a sabbath.

And ye shall take you on the first day the boughs of goodly trees, branches of palm trees, and the boughs of thick trees, and willows of the brook; and ye shall rejoice before the LORD your God seven days.