Sayyiduna Qarazah bin Ka'b al-Ansari (may Allah be pleased with him) narrates from Sayyiduna Umar bin al-Khattab (may Allah be pleased with him): When we set out for Kufah, Sayyiduna Umar bin al-Khattab (may Allah be pleased with him) walked with us on foot to see us off, holding the reins of a donkey or a she-donkey. We said: "O Commander of the Believers! We adjure you by Allah that you must ride," but he refused, until we had travelled three or four miles. Then some of us said to one another: "You have put the Commander of the Believers to hardship," so we dismounted (from our mounts). Then he asked: "Why do you think I came with you as far as this place?" They said: "By it you intended to honour us and to observe the right of the Ansar." He said: "That is indeed so, but along with that, what is (another purpose)?" I said: "We do not know." So he said: "You are going to a people who will be eager to hear many narrations from you, so narrate little from the Messenger of Allah (peace and blessings be upon him), and I am your partner in that."
No one narrated these two hadiths from Mansur bin Abd al-Rahman (may Allah have mercy on him) except Abd al-Aziz bin al-Mukhtar (may Allah have mercy on him).
Hadith Referenceالمعجم الأوسط / باب الألف / 1982
Hadith Takhrij«قال الدارقطني: والصحيح قول من قال عن الشعبي عن قرظة «العلل الواردة في الأحاديث النبوية، ج 2، ص 207»» «أخرجه الحاكم فى «المستدرك» برقم: 347، والدارمي فى «مسنده» برقم: 288، 287، وابن ماجه فى «سننه» برقم: 28، وعبد الرزاق فى «مصنفه» برقم: 20662، وابن أبي شيبة فى «مصنفه» برقم: 67، 33591، 34373، والطحاوي فى «شرح مشكل الآثار» (15/316)، (15/319)، (15/318) [دون رقم في الترقيم المختار]، والطبراني فى «الأوسط» برقم: 2117، 6089»