'Passover' in the Bible

The former exiles observed the Passover on the fourteenth day of the first month

because the priests and descendants of Levi had purified themselves together all of them were pure and they killed the Passover lamb for every former exile, for their relatives the priests, and for themselves.

So the Israelis who had returned from captivity ate the Passover with all who had consecrated themselves from the uncleanness of the nations of the land in order to seek the LORD God of Israel.