Sahih al-Bukhari 3765
Sahih al-Bukhari · Book 62: Companions of the Prophet · Narration about Mu'awiya رضي الله عنه
Narrated Ibn Abi Mulaika:
حَدَّثَنَا ابْنُ أَبِي مَرْيَمَ ، حَدَّثَنَا نَافِعُ بْنُ عُمَرَ ، حَدَّثَنِي ابْنُ أَبِي مُلَيْكَةَ ، قِيلَ لاِبْنِ عَبَّاسٍ هَلْ لَكَ فِي أَمِيرِ الْمُؤْمِنِينَ مُعَاوِيَةَ، فَإِنَّهُ مَا أَوْتَرَ إِلاَّ بِوَاحِدَةٍ. قَالَ إِنَّهُ فَقِيهٌ.
Somebody said to Ibn `Abbas, "Can you speak to the chief of the believers Mu`awiyah, as he does not pray except one rak`a as witr?" Ibn `Abbas replied, "He is a Faqih (i.e. a learned man who can give religious verdicts) ."