I heard Allah's Messenger (ﷺ) as saying: The invoker of curse would neither be witness nor intercessor on the Day of Resurrection.
Sahih Muslim Book 45, Hadith 110
← Previous Hadith This hadith has been narrated on the authority of Zaid b. Aslam with the same chain of transmitters.

Sahih Muslim Book 45, Hadith 109 Next Hadith → Invoke curse upon the polytheists, whereupon he said: I have not been sent as the invoker of curse, but I have been sent as mercy."

Sahih Muslim Book 45, Hadith 111