When we accept Jesus as our savior, we become new creations (Gal 6:15; 2Cor 5:17); God makes our spirit alive and Holy Spirit lives in us to be our guide and much more. (2Cor 3:17).
This exchange of Jesus taking our sin nature (Col 2:14) and giving us His Righteous nature (Gal 3:11,14; 2 Cor 5:17), moves us from living by our senses to living and walking by Faith (2 Cor 5:7).
With our spirit made new, God living inside each of us, our job is to laying aside the old self, and put on the new self (Col 3:9-10; Eph 4:22,24) by renewing the spirit of our minds (Eph 4:23; 2 Cor 3:18)!
One way we are renewing our mind is by taking every thought captive to the obedience of Christ (2Cor 10:3-5), our outer person is decaying, yet our inner person is being renewed day by day as we change our sight to the unseen (2Cor 4:16-18), not rejoicing in unrighteousness, but rejoicing with the truth (1 Cor 13:6).
God is LOVE; we who abide in LOVE abide in God, and God abides in us, and in this LOVE is perfected, as He is so are we in this world (1John 4:16,17).
So do not be conformed to this world, but be transformed by the renewing of your mind that we may prove what is the will of God is, that which is good and acceptable and perfect (Rom 12:2).
There is no fear in LOVE; but perfect LOVE casts out fear, because fear involves punishment (Jesus took our punishment), and the one who fears is not perfected in LOVE (1John 4:18)!