Sahih Ibn Khuzaymah

Hazrat Qais bin Abad narrates that while I was standing in the first row offering prayer in Masjid Nabawi in Madinah Munawwarah, a person pulled me back from behind. He removed me and stood himself in that place. He says, "By Allah, due to anger, I could not comprehend my prayer (what I was reciting)." Then, when he finished the prayer, it was Sayyiduna Ubayy bin Ka'b (may Allah be pleased with him). He said, "O young man, may Allah do good to you. The Prophet of Allah (peace and blessings be upon him) took a covenant from us that we should stand close to the Imam." Then he faced the Qiblah and said, "By the Lord of the Ka'bah, the rulers have perished," and he said this three times. Then he said, "By Allah, I do not feel sorry for them, but I feel sorry for those people who are leading others astray." He says, "I asked, 'Who do you mean by this?' He replied, 'I mean the rulers (leaders).'"