I think a Christian can choose to walk away from God. God would never walk away from us, but can’t we choose to walk away from Him. I don’t think we give up free will once we are born again, do you ?
In John 10:27-30, Jesus said no one could snatch us out of either His or His Father’s hand. It doesn’t say no one but us. In Romans 8:38-39, Paul said nothing could separate us from the love of God. He didn’t say nothing but us.
In Ephesians 1:13-14 he said we were included in Christ when we heard the Gospel of our salvation and believed it. At that time we received the seal of the Holy Spirit as a deposit guaranteeing our inheritance. There’s not a word anywhere in the New Testament about the seal being broken, or the deposit being returned, or the inheritance being canceled, and here’s why.
In 1 Cor 6:19-20, he said we are not our own but have been bought with a price.
In 2 Cor. 1:21-22, he said it’s God who makes us stand firm in Christ. He anointed us, set His seal of ownership on us, and put His spirit in our hearts as a deposit, guaranteeing what is to come. So it’s God who bought us, and the price He paid was the blood of His Son (1 Peter 1:18). To me, this means the decision is irreversible. The Creator of the Universe has made us His own.
“I have revealed and saved and proclaimed– I, and not some foreign god among you. You are my witnesses,” declares the Lord, “that I am God. Yes, and from ancient days I am he. No one can deliver out of my hand. When I act, who can reverse it?” (Isaiah 43:12-14)