Musannaf Ibn Abi Shaybah 4905 — Those who disliked interlacing

Abu Thumamah al-Qammah said: I met Sayyiduna Ka'b (may Allah be pleased with him) at al-Balat, and I had interlaced my fingers. He struck my hand hard and said: We were forbidden from interlacing our fingers in prayer. I said to him: May Allah Almighty have mercy on you, do you see me in prayer? He said: Whoever performs ablution and then sets out for the mosque is in prayer.