At baptism.
Colossians 2:11-12 In whom also ye are circumcised with the circumcision made without hands, in putting off the body of the sins of the flesh by the circumcision of Christ: (12) Buried with him in baptism, wherein also ye are risen with him through the faith of the operation of God, who hath raised him from the dead.
This is why
Romans 6:6 also mentions destroying the body of sins in association with baptism into Christ's death.
Romans 6:3 Know ye not, that so many of us as were baptized into Jesus Christ were baptized into his death?
Romans 6:6 Knowing this, that our old man is crucified with him,
that the body of sin might be destroyed, that henceforth we should not serve sin.
But it is baptism DONE IN FAITH, not just baptism.