Sayyiduna Abdullah bin Umar (may Allah be pleased with them both) narrates: I saw the Messenger of Allah (peace and blessings be upon him) on the pulpit addressing the people. Sayyiduna Hasan bin Ali (may Allah be pleased with him) came out with a piece of cloth around his neck that he was dragging; he tripped over it and fell on his face. The Messenger of Allah (peace and blessings be upon him) came down from the pulpit, heading towards him. When the people saw this, they picked up the child and brought him to him. He took him up in his arms and said: "May Allah destroy Satan! Children are a trial. By Allah, I did not even realise that I had come down from the pulpit until he was brought to me."
Hadith Referenceالمعجم الكبير للطبراني / باب الحاء / 2613