How can Paul die with Christ if Christ is living?

Answer:

"I have been crucified with Christ; it is no longer I who live, but Christ lives in me; and the life which I now live in the flesh I live by faith in the Son of God, who loved me and gave Himself for me" (Galatians 2:20).

The phrase is an allusion to another statement of Paul's:

"Or do you not know that as many of us as were baptized into Christ Jesus were baptized into His death? Therefore we were buried with Him through baptism into death, that just as Christ was raised from the dead by the glory of the Father, even so we also should walk in newness of life. For if we have been united together in the likeness of His death, certainly we also shall be in the likeness of His resurrection, knowing this, that our old man was crucified with Him, that the body of sin might be done away with, that we should no longer be slaves of sin. For he who has died has been freed from sin" (Romans 6:3-7).

Paul is stating in Galatians 2:20 that when he was baptized, he "died" along with Christ. That is, through baptism he symbolically participated in the death of Christ upon the Cross. His old self died, his man of sin, so he no longer lives for his fleshly desires; his life is dedicated to serving Jesus Christ.

Peter made a similar statement:

"Therefore, since Christ suffered for us in the flesh, arm yourselves also with the same mind, for he who has suffered in the flesh has ceased from sin, that he no longer should live the rest of his time in the flesh for the lusts of men, but for the will of God" (I Peter 4:1-2).

In Galatians 2:20, Paul isn't saying that Jesus is currently dead. Quite the opposite. Paul declares that the living Christ can be seen in him as Paul dedicates himself to Christ's service.