Acts 21:23

Do therefore this that we say to thee: We have four men that have a vow on them;

Acts 18:18

And Paul, having tarried after this yet many days, took his leave of the brethren, and sailed thence for Syria, and with him Priscilla and Aquila: having shorn his head in Cenchreae; for he had a vow.

Numbers 6:2-7

Speak unto the children of Israel, and say unto them, When either man or woman shall make a special vow, the vow of a Nazirite, to separate himself unto Jehovah,

Treasury of Scripture Knowledge

Summary

Do therefore this that we say to thee: We have four men which have a vow on them;

Bible References

We have

Acts 18:18
And Paul, having tarried after this yet many days, took his leave of the brethren, and sailed thence for Syria, and with him Priscilla and Aquila: having shorn his head in Cenchreae; for he had a vow.
Numbers 6:2
Speak unto the children of Israel, and say unto them, When either man or woman shall make a special vow, the vow of a Nazirite, to separate himself unto Jehovah,

American Standard Version Public Domain