Numbers 6:14
And he shall offer his offering unto the LORD, one he lamb of the first year without blemish for a burnt offering, and one ewe lamb of the first year without blemish for a sin offering, and one ram without blemish for peace offerings, And he shall offer his offering unto the LORD, one he lamb of the first year without blemish for a burnt offering, and one ewe lamb of the first year without blemish for a sin offering, and one ram without blemish for peace offerings,
The verse lays down the offerings required of a person bringing a Nazarite vow to its completion. At that completion the worshiper was to bring an unblemished male lamb a year old for a burnt offering, an unblemished ewe lamb a year old for a sin offering, and an unblemished ram for peace offerings. These were costly sacrifices that belonged to the purification connected with finishing the vow. In Jerusalem four believers had nearly finished such a vow yet still needed to present these sacrifices, so Paul met their expenses to enable them to complete it and joined with them in the temple ceremonies.