Which one is true?
Both! God changed me in amazing ways, when he first justified me! But, that was only the beginning! During my life, God has been sanctifying me! That requires cooperation, justification does not.
God did some miracles in my life when he saved me - first was that he saved my hard heart. He delivered me from drinking, and he showed me the path I was to walk. But, he left a lot of things for me to work on. God shows me new things daily that I need to repent of. Some things I changed on the outside, but needed God to change on the inside. And sometimes, God let me walk away from something, hence the need to let Christ change me, even 37 years after I was saved.
Justification - God makes us righteous through faith. Romans 5:1
Sanctification - Our walk with God, and all the things he changes with us cooperating. (2 Thess 2:13, 2 Cor. 7:2)
Glorification - When we see Christ face to face, and we become like him. (1 John 3:2; 1 Cor. 13:12) This happens when Christ returns, and we see him face to face.
So, we are being made perfect, but not yet perfect. We need to be changed by the power of God, and then we also need to let God change us, as we walk with him. To better illustrate this:
”[FONT="][/FONT]Do not be conformed to this present world, but be transformed by the renewing of your mind, so that you may test and approve what is the will of God—what is good and well-pleasing and perfect.” Romans 12:2. NET[FONT="]
The word “transformed” in this verse, is [/FONT][FONT="][/FONT][FONT="]μεταμορφοῦσθε[/FONT][FONT="] (metamorphousthe) and is in the present, passive imperative, 2nd person plural. It is a theological passive, in that God is the one who transforms. But, we are commanded to be transformed, which means we have to cooperate with God.
Paul uses exactly the same word in 2 Cor. 3:18, [/FONT][FONT="][/FONT][FONT="]μεταμορφούμεθα[/FONT][FONT="] (metamorphoumetha) except it is 1st person plural. (Present Passive Imperative)
“[/FONT][FONT="][/FONT]And we all, with unveiled faces reflecting the glory of the Lord, are being transformed into the same image from one degree of glory to another, which is from the Lord, who is the Spirit.” 2 Cor. 3:18
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God commands us to let him transform us. So we do need to cooperate although I firmly believe that as believers in Christ, if we resist the Holy Spirit, God will bring us back to the path he has made for us, should we veer away for a short while.
I hope that explanation helps a bit![/FONT]