Hazrat Saeed bin Abi Sadaqah says that I asked Hazrat Ibn Sirin, "If a person sneezes during prayer, what should he do?" He replied, "He should say: 'All praise is due to Allah, Lord of the worlds.'"

Ibrahim says regarding someone who sneezes during prayer, that he should say "Alhamdulillah."

Hasan states regarding a person who sneezes during obligatory or non-obligatory prayer that he should say "Alhamdulillah."

Hazrat Muawiyah bin Hakam Sulami narrates that I was praying with the Prophet (peace and blessings be upon him) when a man sneezed during the prayer, and I said to him, "Yarhamuk Allah" (may Allah have mercy on you). The people started staring at me. I said, "May my mother lose me! Why are you looking at me?" The people began striking their hands on their thighs. When I realized that the people were trying to make me silent, I became silent. Then the Prophet (peace and blessings be upon him) completed the prayer. May my parents be sacrificed for you, I have never seen a better teacher than you before or after; you neither scolded me, nor spoke harshly to me, nor hit me. Then he said, "These prayers do not contain anything of people's speech; prayer is only for glorification, magnification, and recitation."