Sayyiduna Ubaydullah bin Abbas bin Abd al-Muttalib (may Allah be pleased with him), the brother of Sayyiduna Abdullah bin Abbas (may Allah be pleased with them both), narrates: Sayyiduna al-Abbas (may Allah be pleased with him) had a drainpipe that lay on the route of Sayyiduna Umar (may Allah be pleased with him) (during his caliphate). Once, Sayyiduna Umar (may Allah be pleased with him) put on his special clothes on Friday; on that same day two birds had been slaughtered for Sayyiduna al-Abbas (may Allah be pleased with him). When Sayyiduna Umar (may Allah be pleased with him) reached the drainpipe, the blood of the two birds came flowing out of it with water and struck Sayyiduna Umar (may Allah be pleased with him). Sayyiduna Umar (may Allah be pleased with him) ordered the drainpipe to be pulled out. Sayyiduna Umar (may Allah be pleased with him) went back, took off his clothes, put on other clothes, then came and led the people in prayer. (After the prayer) Sayyiduna al-Abbas (may Allah be pleased with him) came to him and said: By Allah, this drainpipe was fixed at the place where the Prophet (peace and blessings be upon him) had fixed it. So Sayyiduna Umar (may Allah be pleased with him) said to Sayyiduna al-Abbas (may Allah be pleased with him): I urge you to climb on my back and put that drainpipe in the very place where the Prophet (peace and blessings be upon him) had fixed it. And Sayyiduna al-Abbas (may Allah be pleased with him) did so.
Ahmad recorded it, and its narrators are thiqat (trustworthy), except that the narrator Hisham bin Sa'd did not hear from Sayyiduna Ubaydullah bin Abbas (may Allah be pleased with them both); and Allah knows best.
Hadith Referenceمجمع الزوائد ومنبع الفوائد / كتاب الأحكام / 7070