If Paul was converted (saved) when he said, ‘Lord, what wilt thou have me to do?’ (Acts 9:6; 22:10), why did he still have sins that needed to be washed away (Acts 22:16)?
It seems that you may be confusing the terms ‘conversion’ and ‘salvation’. Conversion is the initial conviction, the turning from darkness and error to learning God’s way of Salvation, which is the ultimate and eternal deliverance or change from mortality to immortality.
Conversion Is Not Salvation
Nowhere does the Bible say that conversion is the same as salvation. Jesus said plainly that “he who endures to the end shall be saved” (Matt. 24:13). Paul’s conversion was his turning point. He was immediately obedient to the heavenly vision (Gal. 1:16). But this initial conversion did not make him free from sin. Years later he was still fighting sin. In his letter to the Romans he spoke of the struggle he felt between the old nature and the new (Rom. 7:18-23; see also Gal. 5:16-17; Eph. 4:23-24). He compared the Christian life to a race, a fight (1 Cor. 9:25-27), and pictured himself as in the running. He even saw the possibility of falling short and missing the prize if he did not run well enough (see 1 Cor. 9:27). Writing to the Philippians, he said he had not yet achieved? : “Brothers, I do not consider myself yet to have taken hold of it. But one thing I do: Forgetting what is behind and straining toward what is ahead, I press on toward the goal to win the prize for which God has called me heavenward in Christ Jesus” ” (Phil. 3:13-14 NIV). He was still pressing on, if by any means he might “attain to the resurrection from the dead” (Phil. 3:11).
By the end of his life he had triumphed over sin and was ready to face the Judge. He wrote, “I have fought the good fight, I have finished the race, I have kept the faith. Finally, there is laid up for me the crown of righteousness, which the Lord, the righteous Judge, will give to me on that Day” (2 Tim. 4:7-8). Only then was he ready for the great “crown,” salvation.
Paul’s conversion on the Damascus road was only the beginning of a life of service to God.