Ya'qub bin Zayd (may Allah have mercy on him) said that Sayyiduna Umar (may Allah be pleased with him) went out on a Friday, and water from the spout of Sayyiduna al-Abbas (may Allah be pleased with him) fell on him. He (may Allah be pleased with him) ordered that it be pulled out. Sayyiduna al-Abbas (may Allah be pleased with him) said: "You have pulled out my spout. By Allah, the Messenger of Allah (peace and blessings be upon him) fixed it in that place with his own hand." Sayyiduna Umar (may Allah be pleased with him) said: "By Allah, you will put it back with your own hand, and Umar's back will be there for it (to stand on)." So Sayyiduna al-Abbas (may Allah be pleased with him) placed his feet on the shoulders of Sayyiduna Umar (may Allah be pleased with him) and fixed the spout again in the same place.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الصلح / 11363