Sahih Muslim Book 45, Hadith 111
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."
I heard Allah's Messenger (ﷺ) as saying: The invoker of curse would neither be witness nor intercessor on the Day of Resurrection.
Allah's Messenger, the good would reach everyone but it would not reach these two. He said: Why so? I said: Because you have invoked curse and hurled malediction upon both of them. He said: Don't you know that I have made condition with my Lord saying thus: O Allah, I am a human being and that for a Muslim upon whom I invoke curse or hurl malediction make it a source of purity and reward.