'First Day' in the Bible

In the first day you shall have a holy convocation. You shall do no regular work.

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

On the first day shall be a holy convocation: you shall do no regular work.

"'So on the fifteenth day of the seventh month, when you have gathered in the fruits of the land, you shall keep the feast of the LORD seven days: on the first day shall be a solemn rest, and on the eighth day shall be a solemn rest.

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