What may not be done during Prayer and what is permitted - Section 2 Mishkat al-Masabih 994
Arabic hadith text
وَعَنْ كَعْبِ بْنِ عُجْرَةَ قَالَ: قَالَ رَسُولُ اللَّهِ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ: «إِذَا تَوَضَّأَ أَحَدُكُمْ فَأَحْسَنَ وُضُوءَهُ ثُمَّ خَرَجَ عَامِدًا إِلَى الْمَسْجِدِ فَلَا يُشَبِّكَنَّ بَيْنَ أَصَابِعِهِ فَإِنَّهُ فِي الصَّلَاة» . رَوَاهُ أَحْمد وَأَبُو دَاوُد وَالتِّرْمِذِيّ وَالنَّسَائِيّ والدارمي
Translation
Ka‘b b. ‘Ujra reported God’s Messenger as saying, “When one of you performs ablution and does it well, then goes out making for the mosque, he must not interwine his fingers for he is engaged in prayer.” Ahmad, Tirmidhi, Abu Dawud, Nasa’i and Darimi transmitted it.