'Fifteenth' in the Bible

On the fifteenth day of this month shall be a feast, unleavened bread shall be eaten for seven days.

‘Then on the fifteenth day of the seventh month you shall have a holy convocation; you shall do no laborious work, and you shall observe a feast to the Lord for seven days.

They journeyed from Rameses in the first month, on the fifteenth day of the first month; on the next day after the Passover the sons of Israel started out boldly in the sight of all the Egyptians,