Sunan Abi Dawud 24906
In-book no 4402حَدَّثَنَا يُوسُفُ بْنُ مُوسَى، حَدَّثَنَا وَكِيعٌ، عَنِ الأَعْمَشِ، نَحْوَهُ وَقَالَ أَيْضًا حَتَّى يَعْقِلَ . وَقَالَ وَعَنِ الْمَجْنُونِ حَتَّى يُفِيقَ . قَالَ فَجَعَلَ عُمَرُ يُكَبِّرُ .
A similar tradition has also been transmitted by al-A’mash through a different chain of narrators. He also said : “... . Till he reaches puberty , and a lunatic till he is restored to consciousness.” ‘Umar then began to utter: Allah is most great.