Ezra 6:19-22

The Passover 19On the fourteenth day of the first month, the exiles celebrated the Passover. 20The priests and Levites had purified themselves and were all ceremonially clean. The Levites slaughtered the Passover lamb for all the exiles, for their relatives the priests and for themselves. 21So the Israelites who had returned from the exile ate it, together with all who had separated themselves from the unclean practices of their Gentile neighbors in order to seek the LORD, the God of Israel. 22For seven days they celebrated with joy the Festival of Unleavened Bread, because the LORD had filled them with joy by changing the attitude of the king of Assyria so that he assisted them in the work on the house of God, the God of Israel.