As Paul makes his defense in front of Felix and his accusers, he has filled this room with the truth; not only the truth about the events for which he is on trial for, but also the truth that Christianity is linked directly to the OT Scriptures. That being said, notice what he didn’t do—he didn’t resort to personal insults towards his accusers, nor did make it his main ambition to get himself off the hook. Ultimately, he used this opportunity to bring to light the main issue—what Paul is on trial for is mainly with regards to worshipping and serving the Lord God with a clean conscience. When your life is questioned, this is solid ground to stand on. Your life and the way you live your life must ultimately be about worshipping and serving the Lord with a clean conscience:
“I cannot deviate from Scripture if I want to worship the Lord and maintain a clean conscience;”
“I must structure my life to position myself for maximum growth in holiness and usefulness for the Lord’s purposes if I want to worship him as he deserves and maintain a clean conscience;”
“I must fight sin by putting it off, renewing my mind and then putting on righteousness in its place if I want to worship the Lord and maintain a clean conscience.”
On the other hand, if we are constantly getting personally offended and making our defense mainly about ourselves and our opinions, then we are missing the opportunity to glorify Christ! Reason being, that is mainly about our reputation and not about Christ’s. Remember, Jesus told Paul that Paul would be a witness for him, and while Paul and the other apostles certainly had a unique calling on their lives, we must realize that when our lives are questioned, we are being given an opportunity to specifically demonstrate our allegiance to him and what he has said. This puts the main issue on the table and beckons all who are involved to consider their own lives with regards to who or what they are worshipping.
So just to summarize by looking at it from the negative perspective—the best way to defile your conscience in the realm of your witness for Christ is retaliation or a retaliatory spirit. This is being caught up in the supreme injustice of being sinned against and thus the absolute necessity of evening the score. Paul supplies a strong teaching in Rom. 12: 17 Never pay back evil for evil to anyone. Respect what is right in the sight of all men. 18 If possible, so far as it depends on you, be at peace with all men. 19 Never take your own revenge, beloved, but leave room for the wrath of God, for it is written, “Vengeance is Mine, I will repay,” says the Lord. 20 “But if your enemy is hungry, feed him, and if he is thirsty, give him a drink; for in so doing you will heap burning coals on his head.” 21 Do not be overcome by evil, but overcome evil with good.
Ask yourself, what takes the Spirit’s power—retaliation or returning evil with good? What takes a deep and abiding awareness of the example of Christ—retaliation or returning evil with good? The world operates in the former way, but the credibility of a Christian’s witness depends upon the latter.