Sahih Muslim Book 32, Hadith Number 6293.

Chapter : He upon whom Allah’s Apostle (may peace be upon him) invoked curse whereas he in fact did not deserve it, it would be a source of reward and mercy for him.

Salim, the freed slave of Nasriyyin, said: I heard Abu Huraira as saying that he heard Allah’s Messenger (may peace be upon him) as saying: O Allah, Muhammad is a human being. I lose my temper just as human beings lose temper, and I have held a covenant with Thee which Thou wouldst not break: For a believer whom I give any trouble or invoke curse or beat, make that an expiation (of his sins and a source of) his nearness to Thee on the Day of Resurrection.