Hadith 505090
Chapter 15: The Qur'an - كتاب القرآن
حَدَّثَنِي يَحْيَى، عَنْ مَالِكٍ، عَنْ عَبْدِ اللَّهِ بْنِ دِينَارٍ، قَالَ رَآنِي عَبْدُ اللَّهِ بْنُ عُمَرَ وَأَنَا أَدْعُو، وَأُشِيرُ، بِأَصْبُعَيْنِ أَصْبُعٍ مِنْ كُلِّ يَدٍ فَنَهَانِي .
Yahya related to me from Malik that Abdullah ibn Dinar said, "Abdullah ibn Umar saw me when I was making dua and I was pointing with two fingers, one from each hand, and he forbade me."
Reference Muwatta Malik 505090
USC-MSA web (English) reference : Book 15, Hadith 37