Al-Matalib al-'Aliyah 3080 — Travelling in pursuit of knowledge

It is narrated from Sayyiduna Jundub (may Allah be pleased with him) that he said: I came to Madinah in search of knowledge, and I saw people sitting in circles in the Mosque of the Prophet (peace and blessings be upon him), conversing. I kept passing by those circles until I reached a circle in which there was a man whose complexion was pale and who wore two garments, as if he had just returned from a journey. I heard him saying: "By the Lord of the Ka'bah, the people of the knots (those who take charge of affairs of state and offices) have perished, and I feel no grief for them." He said this three times. I sat down with him, and he spoke as much as was decreed for him, then he stood up. When he had risen, I asked: "Who is this?" People said: "This is the master of the Muslims, Sayyiduna Ubayy bin Ka'b (may Allah be pleased with him)." I followed him until he reached his house. I saw that he was in a very simple state and simple clothing; his outward condition and the appearance of his house were alike (in humility). I greeted him with salam, and he returned the greeting, then asked me: "Where are you from?" I said: "From the people of Iraq." He said: "Those who ask the most questions." When he said this, I became angry; I knelt on my knees, faced the qiblah, raised my hands and said: "O Allah, we complain to You about them (the elders). We spend our wealth, wear out our bodies and drive our mounts (in search of knowledge), but when we meet them, they frown at us and say such things to us (mockingly)." On hearing this, Sayyiduna Ubayy (may Allah be pleased with him) began to weep and tried to placate me, and said: "Bless you, come a little closer." Then he supplicated: "O Allah, I make a covenant with You that if You keep me alive until Friday, I will surely speak of all that I heard from the Messenger of Allah (peace and blessings be upon him), and in this matter I will not fear the blame of any blamer." The narrator says: I think he then stood up. When he said this, I took my leave of him and began waiting for Friday in order to hear his talk. When Thursday came, I went out for some need of mine and saw that the streets were crowded with people; whichever street I entered, I found a crowd of people. I asked: "What has happened to the people?" They said: "We think you are a stranger?" I said: "Yes." They said: "The great leader of the Muslims, Sayyiduna Ubayy bin Ka'b (may Allah be pleased with him), has passed away." The narrator says: Then I met Sayyiduna Abu Musa al-Ash'ari (may Allah be pleased with him) in Iraq and told him this story, and he said (with sorrow): "Alas, what a great loss! If only he had lived until he had conveyed to us that saying of the Messenger of Allah (peace and blessings be upon him)."
The chain of this hadith is hasan (good), and its basis is narrated in brief in Sahih Muslim (2497). Musnad Abi Ya'la: 3080; al-Matalib al-'Aliyah: 3091.