مِشْكَاةُ الْمَصَابِيحِ
Mishkat al-Masabih 913
Prayer
The Tashahhud - Section 2
وَعَن أبي هُرَيْرَة قَالَ: إِنَّ رَجُلًا كَانَ يَدْعُو بِأُصْبُعَيْهِ فَقَالَ رَسُولُ اللَّهِ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ: «أَحِّدْ أَحِّدْ» . رَوَاهُ التِّرْمِذِيُّ وَالنَّسَائِيُّ وَالْبَيْهَقِيُّ فِي الدَّعَوَاتِ الْكَبِير
Abu Huraira told how when a man was making supplication using two of his fingers, God’s Messenger said, “Use one, use one.” It is transmitted by Tirmidhi and Nasa’i and by Baihaqi in [Kitab] ad-da'awat al kabir.
Mishkat al-Masabih, 913حسن (الألباني)