Leviticus 5:7

Provision is here made for the poor of God's people, and the pacifying of their consciences under the sense of guilt. Those that were not able to bring a lamb might bring for a sin-offering a pair of turtle-doves or two young pigeons; nay, if any were so extremely poor that they were not able to procure these so often as they would have occasion, they might bring a pottle of fine flour, and this should be accepted. Thus the expense of the sin-offering was brought lower than that of any other offering, to teach us that no man's poverty shall ever be a bar in the way of his pardon. The poorest of all may have atonement made for them, if it be not their own fault. Thus the poor are evangelized; and no man shall say that he had not wherewithal to bear the charges of a journey to heaven. Now, I. If the sinner brought two doves, one was to be offered for a sin-offering and the other for a burnt-offering, Lev 5:7. Observe, 1. Before he offered the burnt-offering, which was for the honour and praise of God, he must offer the sin-offering, to make atonement. We must first see to it that our peace be made with God, and then we may expect that our services for his glory will be accepted. The sin-offering must make way for the burnt-offering. 2.

— Matthew Henry's Concise Commentary (public domain)