Many see Paul's experience where Jesus appeared to him on the road to Damascus as the point in which he received his conversion. (Acts 9:3-6) This is not the case. How can this be known? Because we see his sins were not washed away at that moment. Nor had he received the Holy Ghost. It is at this point, however, that Jesus makes the following statement:
Acts 9:6
And he trembling and astonished said, Lord, what wilt thou have me to do? And the Lord said unto him, Arise, and go into the city, and it shall be told thee what thou must do.
Suffering for the Lord's sake was what Paul
must do. Acts 9:15 - But the Lord said to him, “Go, for he is a chosen vessel of Mine to bear My name before Gentiles, kings, and the children of Israel. 16 For I will show him
how many things he must suffer for My name’s sake.”
What Ananias tells Paul he must do in Acts 9:10-18 and Acts 22:16 parallels exactly what Jesus, Peter, Philip, and Paul himself later told others they must do. After believing in Jesus' death, burial and resurrection everyone, including Paul, was required to be water baptized in the name of Jesus for the remission of sin and receive the Holy Ghost.
In regards to Acts 22:16, as Greek scholar AT Robertson points out, baptism here pictures the washing away of sins by the blood of Christ, but it does not literally wash away our sins, contrary to your conclusion. Jamison, Fausset, and Brown Commentary makes not of the importance of the Greek in Ananias' statement. When Ananias tells Paul to "arise, be baptized, wash away your sins, calling on the name of the Lord," the tense of the last command is literally "having called" (aorist middle participle). "Calling on [epikalesamenos] --- 'having (that is, after having) called on,' referring the confession of Christ which preceded baptism." [Jamison, Fausset, and Brown Commentary, vol. 3 pg. 160]. Kenneth Wuest picks up on this Greek nuance and translates the verse as follows: "And now, why are you delaying? Having arisen, be baptized and wash away your sins, having previously called upon His Name." (Acts 22:16, Wuest's Expanded NT).
In Acts 10:43, receiving remission of sins is connected with
"believes in Him" and not with baptism (Acts 10:43-47). In Acts 9, Jesus told Ananias that Paul "is a chosen vessel unto Me" (vs 15), although the apostle had not yet been water baptized. Before Paul was baptized, Christ had already commissioned him to "bear His name before the Gentiles, and kings, and the children of Israel" (Acts 9:15) and such a commission is not for one who is still lost in their sins. Before Paul’s baptism, Christ had set him aside as one who would "suffer for His name’s sake" (9:16). Can one who is a child of the devil, as all the lost are (Ephesians 2:1-3, John 8:44), really suffer for Christ’s sake? NO.
So, Paul had already believed in Christ when Ananias came to pray for him to receive his sight (Acts 9:17). It also should be noted that Paul at the time when Ananias prayed for him to receive his sight, he was
filled with the Holy Spirit (Acts 9:17)--this was
BEFORE he was water baptized (Acts 9:18). Verse 17 connects his being filled with the Spirit with the receiving of his sight. We know that he received his sight prior to his baptism.
Excellent article on Acts 22:16 -
https://kentbrandenburg.blogspot.com/2015/03/acts-2216-baptism-essential-for.html
*It's interesting that when Paul recounted this event again later in Acts (Acts 26:12-18), he did not mention Ananias or what Ananias said to him at all. Verse 18 again would confirm the idea that Paul received Christ as Savior on the road to Damascus since here Christ is telling Paul he will be a messenger for Him concerning
forgiveness of sins for Gentiles as they have faith in Him. It would seem unlikely that Christ would commission Paul if Paul had not yet believed in Him and was still lost in his sins.
No scripture is to be interpreted in isolation from the totality of scripture. Practically speaking, a singular and obscure verse is to be subservient to to multiple and clear verses, and not vice versa.
Paul's experience is one more example within the word that no one is exempt. All must obey God's NT mandate.
Acts 10:43 - Of Him all the prophets bear witness that through His name everyone who
believes in Him receives forgiveness of sins. *What happened to baptism?
Also, in Acts 13:38-39, we read - Therefore let it be known to you, brethren, that through this Man is preached to you the forgiveness of sins; and by Him everyone who
believes is justified from all things from which you could not be justified by the law of Moses. *What happened to baptism?
Acts 16:30 - And he brought them out and said, “Sirs, what must I do to be saved?” 31 So they said,
“Believe on the Lord Jesus Christ, and you will be saved, you and your household.” *What happened to baptism?
Acts 26:18 - to open their eyes so that they may turn from darkness to light and from the dominion of Satan to God, that they may
receive forgiveness of sins and an inheritance among those who have been
sanctified by faith in Me. *What happened to baptism?
Romans 1:16 - For I am not ashamed of the gospel of Christ, for it is the
power of God to salvation for everyone who believes, for the Jew first and also for the Greek. *What happened to baptism?
Romans 3:24 - Being justified freely by his grace through the redemption that is in Christ Jesus: 25 Whom God hath set forth to be a propitiation through
faith in his blood, to declare his righteousness for the
remission of sins that are past, through the forbearance of God; 26 To declare, I say, at this time his righteousness: that he might be just, and the
justifier of the one who has faith in Jesus. *What happened to baptism?
Romans 4:5 - But to him who does not work but
believes on Him who justifies the ungodly,
his faith is accounted for righteousness, 6 just as David also describes the blessedness of the man to whom
God imputes righteousness apart from works. *What happened to baptism?
Ephesians 2:8 - For
by grace you have been saved through faith, and that
not of yourselves; it is the
gift of God, 9
not of works, lest anyone should boast. *What happened to baptism?