(60) باب إِذَا دَخَلَ الْمَسْجِدَ فَلْيَرْكَعْ رَكْعَتَيْنِ
Narrated Abu Qatada Al-Aslami:
Allah's Messenger (ﷺ) said, "If anyone of you enters a mosque, he should pray two rak`at before sitting." (ES)
Reference (ES): Sahih al-Bukhari 444 (ES)
In-book reference (ES): Book 8, Hadith 93 (ES)
USC-MSA web (English) reference(deprecated numbering scheme): Vol. 1, Book 8, Hadith 435 (ES)