Musannaf Ibn Abi Shayba 3:5644

Abu Bakr narrated to us, he said: Abda narrated to us, from Sufyan, from Ghalib Abu al-Hudhayl, who said: Ibrahim was asked about a man who sneezed during prayer, and another person said to him while he was in the prayer, "May Allah have mercy on you (Yarhamuk Allah)." Ibrahim said: "He only spoke what is good, and he does not have to repeat [the prayer]."