"But when Paul perceived that the one party were Sadducees, and the other Pharisees, he cried out in the council, Men and brethren, I am a Pharisee, the son of a Pharisee: of the hope and resurrection of the dead I am called in question… And the night following the Lord stood by him, and said, Be of good cheer, Paul: for as you have testified of me in Jerusalem, so must you bear witness also at Rome."–Acts 23:6, 11
Paul had his failures, and yet he was not cast out of the ministry because of it.
Scripture says, from Paul's mouth, that a bishop must not be "self-willed" (Titus 1:7). Yet even though he rebelled against God's command, went back to nearly offering sacrifices by the law, and proclaimed himself a Pharisee, after renouncing such distinctions, he still found grace in God's sight and was commissioned from the Lord (Acts 21:4; Acts 21:6; Acts 23:6).
Just because Paul committed self-willed acts, as we do, doesn't mean that he wasn't subject to God and obedient. Every child needs chastisement, because every one fails. But, the Lord's words should encourage us. He says, "so must you bear witness also at Rome", so that His commission didn't change. Paul was STILL sent to bear record of Christ before kings and the Gentiles, as He had said (Acts 9:15).
God brings us TO OBEDIENCE by our falls, as He stands with us. He lets us see what self-will gets us and how it won't work, even as "the night following the Lord stood by him". He gave him a night of hardship to learn the lessons that must be taught, and then He stands by him in condemnation removed, love unchanging, and grace to the poor. He lifts up the heart the He has broken and brings good from man's evil plain. Thus, even though we have sinned, He has not FAILED to wipe away the sins and forgive us completely. And, He will use our disobedience to teach us lessons, so that we minister better. Paul, like you and I, learned humility and dependence on Christ by his recovery from falls. And, like Paul, the lessons that we learn make us useful now.
Scripture says, "Pride goes before destruction, and an haughty spirit before a fall" (Pr 16:18). Therefore, the way of honor is to crown Him Lord, giving glory to Him who died, rose, and gives salvation. It is written, "the most High rules in the kingdom of men, and gives it to whomsoever he will, and sets up over it the basest of men", so that Paul, like you and I, learns that he's useful, not because of greatness in us, but the great mercy of God (Daniel 4:17). And, we're to use His mercy as He sees fit, which is best for us and those to whom we speak. Paul, like you and I, had to learn from his failures, but his failures, like ours, did not disqualify him. He was commissioned, forgiven, and equipped by his falls to minister in humility, giving honor to Christ and salvation by grace.
Likewise, let us learn the lessons of self-will, fleeing from it to Christ. And, let us "Be of good cheer", even as Christ stands by us still (Acts 23:11). And, this "good cheer" or "good courage" is for us in full. We are not to walk around bemoaning ourselves and thinking we can't be used, because we have failed. We are to learn and move on now encouraged in full, not denying the grace and wisdom of God. If He whom we have sinned against, the God of glory, tells us to "be of good cheer", then we must. We must receive the FORGIVENESS of sins, salvation, and commission that we have, and use the lessons learned to help people, rather than allowing the past to close our mouth, dampen our joy, and keep us in regret continually. Let the blood and word of Christ encourage you. Be encouraged by God's wisdom and love. And, know that you and I shall fulfill our commission to preach the gospel, as He has predetermined. When He called us to serve Him, He knew what we'd get ourselves into and the depravity of sin, and yet He planned for and conquered it all, giving victory to us.
All sin and blasphemy shall be forgiven those that trust Christ, and all things, even self-willed rebellion and the pain thereof, shall work together for good to those that love Him (Rom 8:28).
Be of good cheer, brethren. It is not too late to serve Christ: the time is now.