Ziyad bin Subayh narrates: I prayed beside Ibn Umar (may Allah be pleased with them both), and I did not recognise him. During the prayer I placed my hand on my waist, and he pushed my hand away. When I had completed the prayer, I said: What business did you have with me? He said: "You did this, whereas the Messenger of Allah (peace and blessings be upon him) used to forbid the crucifix posture (salb) in prayer."
(b) Makki bin Ibrahim narrated this hadith from Sa'id, and (in his version) he used to forbid placing the hands on the hips in prayer.
(c) It is narrated from Sayyidah Aishah (may Allah be pleased with her) and Ibn Abbas (may Allah be pleased with them both) that they both disliked it.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الصلاة / 3568