It wasnarrated that Muhammad bin `Amr bin `Ata' said, concerning AbuHumaid As-Sa`di:
"I heard him when he was among ten of theCompanionsof the Messenger of Allah (ﷺ), one of whom was AbuQatadah binRib`i, saying: 'I am the most knowledgeable of youabout the prayer of the Messengerof Allah (ﷺ). When he stood up for prayer, hestood up straight andraised his hands until they were parallel tohis shoulders, then hesaid: Allahu Akbar. When he wanted to bow inRuku`, he raised hishands until they were parallel to hisshoulders. When he said Sami`Allahu liman hamidah (Allah hearsthose who praise Him), he raised hishands and stood up straight.When he stood up after two Rak`ah, hesaid Allahu Akbar and raisedhis hands until they were parallel to hisshoulders, as he did whenhe started the prayer.'"
English reference: Vol. 1, Book 5, Hadith 862
Arabic reference: Book 5, Hadith 911