Acts 21:26
So Paul associated with the men; and the next day, having purified himself with them, he went into the Temple, giving every one to understand that the days of their purification were finished, and there he remained until the sacrifice for each of them was offered.
Acts 24:18
While I was busy about these, they found me in the Temple purified, with no crowd around me and no uproar; but there were certain Jews from the province of Asia.
Acts 21:24
Associate with these men and purify yourself with them, and pay their expenses so that they can shave their heads. Then everybody will know that there is no truth in these stories about you, but that in your own actions you yourself scrupulously obey the Law.
1 Corinthians 9:20
To the Jews I have become like a Jew in order to win Jews; to men under the Law as if I were under the Law--although I am not--in order to win those who are under the Law;