'Fifteenth' in the Bible

And on the fifteenth day of this month is the festival. For seven days bread made without yeast must be eaten.

"'On the fifteenth day of the seventh month you are to have a holy assembly; you must do no ordinary work, and you must keep a festival to the Lord for seven days.

They departed from Rameses in the first month, on the fifteenth day of the first month; on the day after the Passover the Israelites went out defiantly in plain sight of all the Egyptians.