The Prophet ﷺ used to lead us in prayer, and he would hold his left hand with his right.
حدثنا عثمان بن أبي شيبة حدثنا أبو الأحوص عن سماك بن حرب
كان النبي ﷺ يؤمنا فيأخذ شماله بيمينه
[Its chain of transmission is hasan] Tirmidhi reported it, Prayer, chapter on placing the right hand over the left in prayer, no. 252, from the hadith of Abu Ahwas with this wording, and he said, a hasan hadith. Ahmad reported it, 5/226, with a sahih chain of transmission, from Simak by his chain with this wording, and in it, "I saw the Prophet ﷺ place this on his chest," meaning in prayer, and its chain of transmission is hasan.