'First Day' in the Bible

God called the light "day" and the darkness "night." There was evening, and there was morning, marking the first day.

The waters kept on receding until the tenth month. On the first day of the tenth month, the tops of the mountains became visible.

In Noah's six hundred and first year, in the first day of the first month, the waters had dried up from the earth, and Noah removed the covering from the ark and saw that the surface of the ground was dry.