20 I have been crucified with Christ, and I no longer live, but Christ lives in me. The life I live in the body, I live by faith in the Son of God, who loved me and gave Himself up for me. -Galatians 2:20 BSB
“I have been crucified with Christ” The cross is a picture of the person’s old nature, his spirit, dying with its sinful desires. Indirectly it is also saying that with Jesus’ resurrection, we are born again having our sins forgiven with eternal life and desiring a life of righteousness for the glory of Christ Jesus.
Therefore if anyone is in Christ, he is a new creation. The old has passed away. Behold, the new has come!2 Corinthians 5:17 BSB
“Christ lives in me” Christ and the Holy Spirit are used in the Scriptures interchangeably as living inside of a person who has professed faith in Jesus Christ.
15 If you love Me, you will keep My commandments. 16 And I will ask the Father, and He will give you another Advocate to be with you forever— 17 the Spirit of truth. The world cannot receive Him, because it neither sees Him nor knows Him. But you do know Him, for He abides with you and will be in you…26 But the Helper, the Holy Spirit, whom the Father will send in My name, He will teach you all things and will bring to your remembrance all things that I have said to you.John 14:15-17, 26 BSB
“The life I live in the body, I live by faith in the Son of God” A believer will no longer live for himself but will live for Jesus Christ, trusting in His Word for guidance and transformation into the image of Christ.