Repent (change your mind).
No one is saved by "personal" faith. If you think so, then you are making your faith your savior and thus, denying the truth. The truth is that you are saved by God through the death, burial, and resurrection of Jesus. That salvation is complete. All that faith can do for us is show that we agree with what God and Jesus have done for us. Faith (believing God) makes us righteous (justified) and gives us peace. We are not saved by that faith, but "justified by faith" (Romans 5:1).
“…solemnly testifying to both Jews and Greeks of repentance toward God and faith in our Lord Jesus Christ.” (Acts 20:21 NASB)
The word repentance is the Greek word metanoian meaning, a change of mind. Paul used it in a similar way in Acts 17:30-31 while in Athens. What Paul was encouraging both the educated orthodox Jew and Greeks (Hellenized Jews and Gentiles) to do was to CHANGE THEIR MIND about God. The false Jewish teaching was that God would only save Jews and those Gentiles who obey the Law of Moses. The Greeks believed in all sorts of false Gods whom they must appease to be saved. Both taught that if they did not appease their God with various rituals they would suffer the eternal wrath of their god. Paul said they needed to repent (change their mind) about the true God and have faith in his Son Christ Jesus. God, in His GRACE, had demonstrated his LOVE for ALL by sending Jesus to show how sinners would be saved. Remember that LOVE is the Greek word agape which means to be charitable without expecting anything in return. And the word grace means unmerited favor.
Paraphrases of the bible (The Message and the New Living Translation, for example) alter and add words to the Scripture, which often hide the truth of the passage. Read the above verse in one of these paraphrases and see how they differ from the above NASB direct translation. These paraphrases actually add and change the Greek words found in the oldest Greek manuscripts. The only way people find out about this deception is to look at a good Greek Lexicon - which few seem to do preferring to trust and quote these easy reading paraphrases of men. Nevertheless, the truth is the truth whether one believes it or not.
"As in Adam all die, even so in Christ shall All be made alive....that God may be All in All" (1 Corinthians 15:22-28)
I suppose people think they are saved by their personal faith because of what Paul told the Philippian jailer when the jailer asked, "What shall I DO to be saved?" Paul's response implies he and his family did not have to DO anything. They can have faith (belief) in the finished work of their Savior, the "Lord Jesus Christ." Paul was not telling him that his personal faith would save he and his family, but to believe that the Savior, Christ Jesus, HAS AND WILL save he and his family.