22:16 Arise, and be baptized. Dean Howson ( Acts, p. 501) says that the verb baptize in the Greek is in the middle voice, and that a more accurate rendering would be, Have thyself baptized.
Wash away thy sins. This language shows that Ananias thought that the penitent sinner was to be baptized for the remission of sins (Ac 2:38), and that Paul held the same view. Compare Titus 3:5. Hackett says:
This clause states the result of baptism in language derived from the nature of the ordinance. It answers to eis aphesin hamartion (Ac 2:38), i.e. submit to the rite in order to be forgiven.... There can be no question of the mode of baptism in this case, for if it be held that be baptized is uncertain in its meaning, wash away is a definition that removes the doubt.''
As the final act of conversion, baptism symbolically, is said to wash away sins.
22:16 Be baptized, and wash away thy sins - Baptism administered to real penitents, is both a means and seal of pardon. Nor did God ordinarily in the primitive Church bestow this on any, unless through this means.
22:12-21 The apostle goes on to relate how he was confirmed in the change he had made. The Lord having chosen the sinner, that he should know his will, he is humbled, enlightened, and brought to the knowledge of Christ and his blessed gospel. Christ is here called that Just One; for he is Jesus Christ the righteous. Those whom God has chosen to know his will, must look to Jesus, for by him God has made known his good-will to us. The great gospel privilege, sealed to us by baptism, is the pardon of sins. Be baptized, and wash away thy sins; that is, receive the comfort of the pardon of thy sins in and through Jesus Christ, and lay hold on his righteousness for that purpose; and receive power against sin, for the mortifying of thy corruptions. Be baptized, and rest not in the sign, but make sure of the thing signified, the putting away of the filth of sin. The great gospel duty, to which by our baptism we are bound, is, to seek for the pardon of our sins in Christ's name, and in dependence on him and his righteousness. God appoints his labourers their day and their place, and it is fit they should follow his appointment, though it may cross their own will. Providence contrives better for us than we do for ourselves; we must refer ourselves to God's guidance. If Christ send any one, his Spirit shall go along with him, and give him to see the fruit of his labours. But nothing can reconcile man's heart to the gospel, except the special grace of God.