Sayyiduna Jabir bin Samurah (may Allah be pleased with him) narrates this about the Noble Prophet (peace and blessings of Allah be upon him): He came to the mosque and saw some people raising their hands, so he said: "These people have raised their hands like the tails of unruly horses. You should remain in a state of calmness during prayer."
Hadith Referenceصحیح ابن حبان / كتاب الصلاة / 1879
Hadith Gradingفضيلة الشيخ الإمام محمد ناصر الدين الألبانيصحيح: م - انظر ما قبله.فضيلة الشيخ العلّامة شُعيب الأرناؤوطإسناده صحيح على شرط مسلم.