Sahih al-Bukhari
Sahih al-Bukhari 478, 479
To clasp one's hands by interlocking the fingers in the mosque or outside the mosque
Arabic hadith text
حَدَّثَنَا حَامِدُ بْنُ عُمَرَ، عَنْ بِشْرٍ، حَدَّثَنَا عَاصِمٌ، حَدَّثَنَا وَاقِدٌ، عَنْ أَبِيهِ، عَنِ ابْنِ عُمَرَ، أَوِ ابْنِ عَمْرٍوشَبَّكَ النَّبِيُّ صلى الله عليه وسلم أَصَابِعَهُ.
Translation
Narrated Ibn `Umar or Ibn `Amr
The Prophet (ﷺ) clasped his hands, by interlacing his fingers.