# But even if we or an angel from heaven should proclaim ... let him be cursed

Paul said this to show how strongly he felt about anyone who might proclaim a gospel other than the one he had proclaimed. If anyone would do that, that person should be cursed. Alternate translation: "But even if we or an angel from heaven were to preach ... let him be cursed"

# But even if we or an angel from heaven should proclaim

The word "even" shows that Paul did not believe that he or an angel from heaven would ever proclaim a different gospel. But he includes himself and angels in his statement to emphasize how wrong it would be for anyone to proclaim a different gospel.

# other than the one

"different from the gospel" or "different from the message"

# let him be cursed

"let him be condemned" or "God should punish that person forever."