Our acceptance of baptism is only acceptance of God’s gift.
This is emphasized strongly in the addition: “for or unto remission of your sins.” It amounts to nothing more than a formal grammatical difference whether εἰς is again regarded as denoting sphere (equal to ἐν), R. 592, or, as is commonly supposed, as indicating aim and purpose, R. 592, or better still as denoting effect. Sphere would mean that baptism is inside the same circle as remission; he who steps into this circle has both. Aim and purpose would mean that baptism intends to give remission; in him, then, who receives baptism aright this intention, aim, and purpose would be attained. The same is true regarding the idea of effect in εἰς. This preposition connects remission so closely with baptism that nobody has as yet been able to separate the two. It is this gift of remission that makes baptism a true sacrament; otherwise it would be only a sign or a symbol that conveys nothing real. In order to make baptism such a symbol, we are told that Peter’s phrase means only that baptism pictures remission, a remission we may obtain by some other means at some later day. But this alters the force of Peter’s words. Can one persuade himself that Peter told these sinners who were stricken with their terrible guilt to accept a baptism that pointed to some future remission? Had he no remission to offer them now? And when and how could they get that remission, absolutely the one thing they must have? And how can Ananias in 22:16 say, “Be baptized and wash away thy sins!” as though the water of baptism washed them away by its connection with the Name?
Ἄφεσις, from ἀφίημι, “to send away,” is another great Biblical concept: “the sending away” of your sins. How far away they are sent Ps. 103:12 tells us: “as far as the east is from the west, so far has he removed our transgressions from us.” Measure the distance from the point where the east begins to the point where the west ends. Nor does David say, “as far as the north is from the south,” lest you think of the poles and succeed in measuring the distance. Again Micah 7:19: “Thou wilt cast all their sins into the depths of the sea.” Even today the sea has depths that have never been sounded. The idea to be conveyed is that the sins are removed from the sinner so as never to be found again, never again to be brought to confront him. God sends them away, and he would thus be the last to bring them back. When the sinner appears before his judgment seat, his sins are gone forever. This is what our far less expressive “forgiveness” really means. Nor does the guilt remain, for sin and guilt are one: sin gone, guilt gone! (Lenski, R. C. H. (1961). The Interpretation of the Acts of the Apostles (pp. 107–108). Minneapolis, MN: Augsburg Publishing House.)
