Amir al-Ahwal (may Allah have mercy on him) narrates: I asked Ata' (may Allah have mercy on him) about letting the garment hang down, and he declared it disliked (makruh). I asked: "Is this established from the Prophet (peace and blessings be upon him)?" He said: "Yes, it is established."
Note: Letting the garment hang down on both sides from the head or the shoulders in prayer is called "al-sadl".
(b) It has been reported to us from Ata' bin Abi Rabah (may Allah have mercy on him) that he prayed with his garment hanging down.
(c) Perhaps he had forgotten this hadith, or he understood it to mean that it is impermissible only when done out of arrogance, and he did not do it out of arrogance. And Allah knows best.
Although this chain is munqati' (broken), it gives strength to the two connected narrations before it.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الصلاة / 3310