Sunan Abi Dawud 61
سنن أبي داود#61Sahihحَدَّثَنَا عُثْمَانُ بْنُ أَبِي شَيْبَةَ، حَدَّثَنَا وَكِيعٌ، عَنْ سُفْيَانَ، عَنِ ابْنِ عَقِيلٍ، عَنْ مُحَمَّدِ ابْنِ الْحَنَفِيَّةِ، عَنْ عَلِيٍّ، رضى الله عنه قَالَ قَالَ رَسُولُ اللَّهِ صلى الله عليه وسلم " مِفْتَاحُ الصَّلاَةِ الطُّهُورُ وَتَحْرِيمُهَا التَّكْبِيرُ وَتَحْلِيلُهَا التَّسْلِيمُ " .
Narrated Ali ibn AbuTalib: The key to prayer is purification; its beginning is takbir and its end is taslim
Scholarly Authentication
The label above is the grade most of these scholars gave, each scholar counted once — one dissenting opinion no longer speaks for all of them. If any scholar calls a narration fabricated, that verdict is shown instead, whatever the others say. When they judged only its chain of narrators (“Isnaad”), the label says “Sound chain”. Each scholar's own wording:
Our source also lists this ruling under Muhammad Muhyi Al-Din Abdul Hamid, the editor of the printed edition it was taken from. It is al-Albani's ruling printed again, so it is counted once.
In-book reference: 1:61