Musannaf Ibn Abi Shayba 17:680

Yazid ibn Harun narrated to us, from Muhammad ibn Ishaq, from Mus'ab ibn Abd al-Rahman ibn Dhu'ayb, who said: A man sneezed in the presence of Ibn al-Zubayr, so he said "Yarhamuk Allah" (may Allah have mercy on you) to him. Then he sneezed, and he said "Yarhamuk Allah" to him. Then he sneezed a third time, and he said "Yarhamuk Allah" to him. Then he sneezed a fourth time, and Ibn al-Zubayr said to him: "You are congested, so blow your nose."