Hadithcore
Riyad as-Salihin, 882

Abu Hurairah (May Allah be pleased with him) reported:

Whenever the Messenger of Allah (ﷺ) sneezed, he would cover his mouth with his hand or a piece of cloth - thereby suppressing the sound. <b>[Abu Dawud and At-Tirmidhi]</b>.

وعن أبي هريرة رضي الله عنه قال‏:‏ كان رسول الله صلى الله عليه وسلم إذا عطس وضع يده أو ثوبه علي فيه، وخفض -أو غض- بها صوته‏.‏ شك الراوي‏.‏ ‏(‏‏(‏رواه أبو داود، والترمذي وقال‏:‏ حديث حسن صحيح‏)‏‏)‏‏.‏

References1 variant
In-Book Reference
Book 5, Hadith 39
Sharh · explanationclick to expand
<b>Guidance from the Hadith:</b><br> 1) The Prophet’s practical manners with regard to sneezing include putting the hand or clothes on the face. This serves a number of good purposes, including the following:<br> a. It protects those around the sneezing person, lest something harmful and contagious comes out with the sneeze and infects them.<br> b. This spares people any feeling of disgust from what comes out of the nose with sneezing.<br> 2) The Shariah honors the believer by its overall guidelines which he should observe towards himself and others.<br> 3) It is recommended to lower the sound of sneezing to avoid bothering those around.