Sahih al-Bukhari 1167
Book 19: Prayer at Night (Tahajjud) · Narrated by Abu Qatada bin Rabi Al-Ansari
Arabic
حَدَّثَنَا الْمَكِّيُّ بْنُ إِبْرَاهِيمَ، عَنْ عَبْدِ اللَّهِ بْنِ سَعِيدٍ، عَنْ عَامِرِ بْنِ عَبْدِ اللَّهِ بْنِ الزُّبَيْرِ، عَنْ عَمْرِو بْنِ سُلَيْمٍ الزُّرَقِيِّ، سَمِعَ أَبَا قَتَادَةَ بْنَ رِبْعِيٍّ الأَنْصَارِيّ َ ـ رضى الله عنه ـ قَالَ قَالَ النَّبِيُّ صلى الله عليه وسلم " إِذَا دَخَلَ أَحَدُكُمُ الْمَسْجِدَ فَلاَ يَجْلِسْ حَتَّى يُصَلِّيَ رَكْعَتَيْنِ ".
English translation
Narrated Abu Qatada bin Rabi Al-Ansari:The Prophet (ﷺ) said, "If anyone of you enters a Mosque, he should not sit until he has offered a two-rak`at prayer
Reference: Sahih al-Bukhari 1167, Book of Prayer at Night (Tahajjud). English translation by Dr. Muhammad Muhsin Khan.