Pigeons are mentioned as among the offerings which, by divine appointment, Abram presented unto the Lord (Gen. 15:9). They were afterwards enumerated among the sin-offerings (Lev. 1:14; 12:6), and the law provided that those who could not offer a lamb might offer two young pigeons (5:7; comp. Luke 2:24). (See DOVE.)
Pigeon
A lamb was costly, and the law made room for people who did not have one. In Leviticus, “if he be not able to bring a lamb,” he may bring “two turtledoves, or two young pigeons” instead, one as a sin offering and the other as a burnt offering. The same allowance appears for a woman after childbirth and for a person being made clean, where the offering is “such as he is able to get.” A young pigeon also appears much earlier, among the animals Abram brings in Genesis 15:9. The pattern is gentle: the gift is fitted to what a person can actually carry, and the priest still makes atonement.
5 verses
Genesis
And he said unto him, Take me an heifer of three years old, and a she goat of three years old, and a ram of three years old, and a turtledove, and a young pigeon.
Leviticus
And if the burnt sacrifice for his offering to the LORD be of fowls, then he shall bring his offering of turtledoves, or of young pigeons.
And if he be not able to bring a lamb, then he shall bring for his trespass, which he hath committed, two turtledoves, or two young pigeons, unto the LORD; one for a sin offering, and the other for a burnt offering.
And if she be not able to bring a lamb, then she shall bring two turtles, or two young pigeons; the one for the burnt offering, and the other for a sin offering: and the priest shall make an atonement for her, and she shall be clean.
And two turtledoves, or two young pigeons, such as he is able to get; and the one shall be a sin offering, and the other a burnt offering.
From Easton's Bible Dictionary
Matthew George Easton, 1897