I heard Musab bin Saad say, "I prayed beside my father, and I joined my palms together and placed them between my thighs. My father forbade me from doing so and said, 'We used to do this, but we were forbidden from it and were commanded to place our hands on our knees.'"
سمعت مصعب بن سعد يقول: صليت إلى جنب أبي، فطبقت بين كفي، ثم وضعتهما بين فخذي، فنهاني أبي وقال: كنا نفعله فنهينا عنه، وأمرنا أن نضع أيدينا على الركب.
Bukhari narrated it in the Book of Adhan (790), and Muslim in the Book of Mosques (535), both through the route of Abu Yafur with similar wording, and the wording given here is Bukhari's.In Muslim's wording, "I put my hand between my knees, so my father said to me, 'Strike your palms upon your knees.'" He said, "Then I did that again, so he struck my hand and said, 'We were forbidden to do this, and we were commanded to strike our palms upon our knees.'"In another narration of his, through the route of Zubayr bin Adi, from Musab bin Saad bin Abu Waqqas, who said, "I prayed beside my father, and when I bowed I interlaced my fingers and put them between my knees, so he struck my hand. Then when he finished praying, he said, 'We used to do this, then we were commanded to raise our hands up to the knees.'"Tirmidhi said (2/44), "This is the practice followed by the people of knowledge among the companions of the Prophet ﷺ, the successors, and those who came after them, with no disagreement among them concerning this, except what has been reported from Ibn Masud and some of his companions, that they used to clasp their hands together between the knees, but this practice is considered abrogated according to the people of knowledge."The hadith of Abdullah bin Masud will follow.