Al-Matalib al-'Aliyah 3806 — The blessing of the supplication

It is narrated from Sayyiduna Abdullah bin Umar (may Allah be pleased with them both) that the Messenger of Allah (peace and blessings be upon him) came out one morning and said: "Before the Fajr prayer today I saw (in a dream) as though I had been given 'al-maqalid' (the keys) and 'al-mawazin' (the scales). As for 'al-maqalid', they are these keys, and as for 'al-mawazin', they are the scales with which things are weighed. I was placed in one pan of the scale and my whole Ummah was placed in the other pan; I was weighed and I outweighed my Ummah. Then Sayyiduna Abu Bakr (may Allah be pleased with him) was brought and weighed, and he too outweighed them all. Then Sayyiduna Umar (may Allah be pleased with him) was brought and weighed, and he too outweighed them all. Then Sayyiduna Uthman (may Allah be pleased with him) was brought and weighed, and he too proved heavier than them all. Then I woke up, and they (the scales and keys) were taken away."
Imam Ahmad narrated this hadith in his Musnad (5361) and Imam al-Bazzar (2460), and its chain is of hasan (good) grade.