Acts 21:26
Then Paul took the men, and the next day he purified himself along with them and went into the temple, giving notice when the days of purification would be fulfilled and the offering presented for each one of them.
Acts 24:18
While I was doing this, they found me purified in the temple, without any crowd or tumult. But some Jews from Asia--
Numbers 6:13-20
"And this is the law for the Nazirite, when the time of his separation has been completed: he shall be brought to the entrance of the tent of meeting,
Acts 21:24
take these men and purify yourself along with them and pay their expenses, so that they may shave their heads. Thus all will know that there is nothing in what they have been told about you, but that you yourself also live in observance of the law.
1 Corinthians 9:20
To the Jews I became as a Jew, in order to win Jews. To those under the law I became as one under the law (though not being myself under the law) that I might win those under the law.