'First Day' in the Bible

Then shall be separate unto Yahweh his days of separation, and shall bring in a he-lamb a year old as a guilt-bearer, - and, the first days, shall be lost because his separation, was made unclean.

And so it was, that, he who on the first day, offered his oblation, - was Nahshon son of Amminadab of the tribe of Judah;

On the first day, a holy convocation, - no laborious work, shall ye do;