Mustadrak al-Hakim — Hadith 8817

It is narrated from Qays bin Ubad that he said: I used to come to Madinah to meet the Companions of the Messenger of Allah (peace and blessings be upon him), and of all of them, the one I most loved to meet was Sayyiduna Ubayy bin Ka'b (may Allah be pleased with him). He says: I came to Madinah in the time of Sayyiduna Umar (may Allah be pleased with him). The iqamah was called for the Fajr prayer, and Sayyiduna Umar (may Allah be pleased with him) came out, and some other men were with him. A man from among the people began looking at the faces of the people; he recognised them but did not recognise me, so he pushed me (back from the row) and stood in my place. I prayed, but (because of the push) I was not aware of my prayer. When they had finished praying, he said: O my son! May Allah not cause you harm. I did not do what I did out of ignorance; rather, the Messenger of Allah (peace and blessings be upon him) instructed us: "Be in the row that is next to me" (those of you who are people of understanding and wisdom), and I looked at the faces of the people and recognised all of them except you. Then he sat down, and I have never seen people's necks strain towards anything as much as they strained towards him (out of reverence). It turned out that he was Sayyiduna Ubayy bin Ka'b (may Allah be pleased with him). Among the things he said was: "By the Lord of the Ka'bah! The people of covenants (those in authority) are ruined. By the Lord of the Ka'bah! The people of covenants are ruined. By Allah, I do not grieve for them; I only grieve for the Muslims whom they have ruined."
This hadith has a sahih (authentic) chain of narration, but the two Shaykhs (Bukhari and Muslim) did not record it.