To become a Christian not only entails what we confess and believe, although most assuredly we must do both. But at the most profound level it is something God does for us and to us.

“because, if you confess with your mouth that Jesus is Lord and believe in your heart that God raised him from the dead, you will be saved.”
(Rom 10:9 ESV)

“Jesus answered him, “Truly, truly, I say to you, unless one is born again* he cannot see the kingdom of God.””
(John 3:3 ESV)

“ Blessed be the God and Father of our Lord Jesus Christ! According to his great mercy, he has caused us to be born again to a living hope through the resurrection of Jesus Christ from the dead,”
(1Pet 1:3 ESV)

“since you have been born again, not of perishable seed but of imperishable, through the living and abiding word of God;”
(1Pet 1:23 ESV)

To become a Christian is to have a supernatural event transacted for us and in us. We must will and do, but it is God working in us that brings us to faith and brings about our willing and doing.

“ Therefore, my beloved, as you have always obeyed, so now, not only as in my presence but much more in my absence, work out your own salvation with fear and trembling, for it is God who works in you, both to will and to work for his good pleasure.”
(Phil 2:12-13 ESV)

What God does through the finished work of His Son in the lives of His children is supernatural, it is effectual, it is irrevocable, and it is wonderful.

“And I am sure of this, that he who began a good work in you will bring it to completion at the day of Jesus Christ.”
(Phil 1:6 ESV)

“But the one who endures to the end will be saved.”
(Matt 24:13 ESV)

“who will sustain you to the end, guiltless in the day of our Lord Jesus Christ.”
(1Cor 1:8 ESV)