It wasnarrated from Abu Hurairah that the Messenger of Allah (ﷺ)said:
"When anyone of you enters the mosque, let him not sit downuntilhe performs two Rak'ah." (RU)
English reference (RU): Vol. 1, Book 5, Hadith 1012 (RU)
Arabic reference (RU): Book 5, Hadith 1065 (RU)