Musnad Abu Ya'la al-Mawsili 161:15

Ishaq narrated to us, Khalid bin al-Harith narrated to us, from Muhammad bin ‘Ajlan, from Sumayy, from Abu Salih, from Abu Hurayrah, who said: When the Messenger of Allah (peace be upon him) would sneeze, he would lower his voice with it and cover his face.