Cross reference
Acts 21:23
23 Do therefore this that we say to thee: We have four men that have a vow on them;
Acts 18:18
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
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,
3 he shall separate himself from wine and strong drink; he shall drink no vinegar of wine, or vinegar of strong drink, neither shall he drink any juice of grapes, nor eat fresh grapes or dried.
4 All the days of his separation shall he eat nothing that is made of the grape-vine, from the kernels even to the husk.
5 All the days of his vow of separation there shall no razor come upon his head: until the days be fulfilled, in which he separateth himself unto Jehovah, he shall be holy; he shall let the locks of the hair of his head grow long.
6 All the days that he separateth himself unto Jehovah he shall not come near to a dead body.
7 He shall not make himself unclean for his father, or for his mother, for his brother, or for his sister, when they die; because his separation unto God is upon his head.