Arabic text
عن أبي هريرة رضي الله عنه قال: كان رسولُ الله صلى الله عليه وسلم إذا عَطَس وضَعَ يَدَه -أو ثوبَهُ- على فيهِ، وخَفَضَ -أو غضَّ- بها صوتَهُ.
Translation
Abu Hurayrah (may Allah be pleased with him) reported: Whenever the Messenger of Allah (may Allah's peace and blessings be upon him) sneezed, he would put his hand—or his garment—over his mouth and lower—or drop—his voice therewith.
Explanation
Whenever the Prophet (may Allah's peace and blessings be upon him) sneezed: First: He would put his hand or garment over his mouth so that nothing would come out of his mouth or nose and hurt those around him. Second: He would lower his voice and not raise it.
Source: HadeethEnc.com