Musnad Ahmad 1153:483

Khalaf ibn al-Walid narrated to us, he said: Abu Ma'shar narrated to us, from 'Abdullah ibn Yahya, from 'Amrah bint 'Abd al-Rahman, from 'A'ishah, she said: A man sneezed in the presence of the Messenger of Allah, may Allah bless him and grant him peace. He said: "What should I say, O Messenger of Allah?" He said: "Say: 'Al-hamdu lillah' (Praise be to Allah)." The people said: "What should we say to him, O Messenger of Allah?" He said: "Say to him: 'Yarhamuk Allah' (May Allah have mercy on you)." He said: "What should I say to them, O Messenger of Allah?" He said: "Say to them: 'Yahdikum Allah wa yuslih balakum' (May Allah guide you and rectify your state)."