"I am with you in spirit." Being with them in spirit represents caring about them or wanting to be with them. AT: "I care about you" or "I want to be with you"
Possible meanings are 1) the name of the Lord Jesus is a metonym that represents his authority. AT: "with the authority of our Lord Jesus" or 2) being assembled in the Lord's name implies meeting together to worship him. AT: "to worship our Lord Jesus" (See: [[rc://en/ta/man/translate/figs-metonymy]] and [[rc://en/ta/man/translate/figs-explicit]])
Handing the man over to Satan represents not allowing the man to be part of their group so that Satan would be allowed to harm him. AT: "make this man leave your group so that Satan can harm him" (See: [[rc://en/ta/man/translate/figs-metaphor]])
Possible meanings are 1) "flesh" refers to his physical body. AT: "so that Satan may harm his body" or 2) "flesh" is a metaphor for the sinful nature. AT: "so that his sinful nature will be destroyed" or "so that he will not continue to live according to his sinful nature" (See: [[rc://en/ta/man/translate/figs-metaphor]])
# so that his spirit may be saved on the day of the Lord
This can be stated in active form. AT: "so that God may save his spirit on the day of the Lord" (See: [[rc://en/ta/man/translate/figs-activepassive]])