New Revised Standard Version
Join these men, go through the rite of purification with them, and pay for the shaving of their heads. Thus all will know that there is nothing in what they have been told about you, but that you yourself observe and guard the law.

Contemporary English Version
Join with them and prepare yourself for the ceremony that goes with the promises. Pay the cost for their heads to be shaved. Then everyone will learn that the reports about you are not true. They will know you do obey the Law of Moses.

New American Bible
Take these men and purify yourself with them, and pay their expenses that they may have their heads shaved. In this way everyone will know that there is nothing to the reports they have been given about you but that you yourself live in observance of the law.

Douay-Rheims Bible
Take these and sanctify thyself with them: and bestow on them, that they may shave their heads. And all will know that the things which they have heard of these are false: but that thou thyself also walkest keeping the law.

Take these and sanctify thyself with them: and bestow on them, that they may shave their heads. And all will know that the things which they have heard of these are false: but that thou thyself also walkest keeping the law.

and purify.

Acts 21:26 Then Paul took the men and, the next day being purified with them, entered into the temple, giving notice of the accomplishment of the days of purification, until an oblation should be offered for every one of them.

Acts 24:18 In which I was found purified in the temple: neither with multitude nor with tumult.

Exodus 19:10,14 And he said to him: Go to the people, and sanctify them to day, and to morrow, and let them wash their garments. . . .

Numbers 19:17-22 And they shall take of the ashes of the burning and of the sin offering, and shall pour living waters upon them into a vessel. . . .

2 Chronicles 30:18,19 For a great part of the people from Ephraim, and Manasses, and Issachar, and Zabulon, that had not been sanctified, ate the phase otherwise than it is written: and Ezechias prayed for them, saying: The Lord who is good will shew mercy, . . .

Job 1:5 And when the days of their feasting were gone about, Job sent to them, and sanctified them: and rising up early, offered holocausts for every one of them. For he said: Lest perhaps my sons have sinned, and have blessed God in their hearts. So did Job all days.

Job 41:25 When he shall raise him up, the angels shall fear, and being affrighted shall purify themselves.

John 3:25 And there arose a question between some of John's disciples and the Jews, concerning purification.

Hebrews 9:10-14 And divers washings and justices of the flesh laid on them until the time of correction. . . .

that they.

Acts 18:18 But Paul, when he had stayed yet many days, taking his leave of the brethren, sailed thence into Syria (and with him Priscilla and Aquila), having shorn his head in Cenchrae. For he had a vow.

Numbers 6:5,9,13,18 All the time of his separation no razor shall pass over his head, until the day be fulfilled of his consecration to the Lord. He shall be holy, and shall let the hair of his head grow. . . .

Judges 13:5 Because thou shalt conceive, and bear a son, and no razor shall touch his head: for he shall be a Nazarite of God, from his infancy, and from his mother's womb, and he shall begin to deliver Israel from the hands of the Philistines.

Judges 16:17-19 Then opening the truth of the thing, he said to her: The razor hath never come upon my head, for I am a Nazarite, that is to say, consecrated to God from my mother's womb: If my head be shaven, my strength shall depart from me, and I shall become weak, and shall be like other men. . . .

but.

1 Corinthians 9:20 And I became to the Jews a Jew, that I might gain the Jews:

Galatians 2:12 For before that some came from James, he did eat with the Gentiles: but when they were come, he withdrew and separated himself, fearing them who were of the circumcision.