When any one of you enters the mosque, he should observe two rak'ahs (of Nafl prayer) before sitting.
Sahih Muslim Book 6, Hadith 84
← Previous Hadith A hadith like this has been narrated from the Messenger of Allah (ﷺ) by Abu Usaid.

Sahih Muslim Book 6, Hadith 83 Next Hadith → I entered the mosque, when the Messenger of Allah (ﷺ) had been sitting among people, and I also sat down among them. Upon this the Messenger of Allah (ﷺ) said: What prevented you from offering two rak'ahs (of Nafl prayer) before sitting down? I said: Messenger of Allah, I saw you sitting and people sitting (around you and I, therefore, sat in your company). He (the Holy Prophet) then said: When anyone among you enters the mosque, he should not sit till he has observed two rak'ahs.

Sahih Muslim Book 6, Hadith 85