Adam Clarke on Matthew 6:14

If ye forgive men - He who shows mercy to men receives mercy from God. For a king to forgive his subjects a hundred millions of treasons against his person and authority, on this one condition, that they wilt henceforth live peaceably with him and with each other, is what we shall never see; and yet this is but the shadow of that which Christ promises on his Father's part to all true penitents. A man can have little regard for his salvation, who refuses to have it on such advantageous terms. See Quesnel.