Ezra 6:20-21

20For the priests and the Levites had purified themselves together; all of them were [ceremonially] clean. So they slaughtered the Passover lamb for all the exiles, for their brothers the priests, and for themselves.

21The Passover was eaten by the sons (descendants) of Israel (Jacob) who returned from exile and by all those who had separated themselves from the [ceremonial] uncleanness of the nations of the land to join them, in order to seek the Lord God of Israel.