It is narrated from Sayyiduna Wa'il bin Hujr (may Allah be pleased with him) that when the Prophet (peace and blessings be upon him) stood in prayer, he would hold his left hand with his right hand. (The narrator Musa bin Umayr said:) And I saw Alqamah doing so as well.
Hadith Referenceالمعجم الكبير للطبراني / باب الواو / 18221