Sulaym bin Amir (may Allah have mercy on him) said: Sayyiduna Abu Umamah (may Allah be pleased with him) told them that at the time of the Isha prayer the Messenger of Allah (peace and blessings be upon him) ordered his Companions: "Gather for the prayer tomorrow, for I have a matter for you." A group of them said: "O so-and-so, write down the first word the Messenger of Allah (peace and blessings be upon him) speaks, and you write the one after it," so that nothing of the speech of the Messenger of Allah (peace and blessings be upon him) would escape them. When he (peace and blessings be upon him) finished the Fajr prayer, he said: "Have you gathered as I ordered you?" The Companions said: "Yes, O Messenger of Allah." He said: "Worship Allah and do not associate anything with Him. Have you understood this? Have you understood this? Have you understood this?" The Companions said: "Yes." He said: "Establish the prayer and pay the zakah; establish the prayer and pay the zakah; establish the prayer and pay the zakah. Have you understood this? Have you understood this? Have you understood this?" The Companions said: "Yes." He said: "Listen and obey; listen and obey. Have you understood this? Have you understood this? Have you understood this?" The Companions said: "Yes." We had thought that the Messenger of Allah (peace and blessings be upon him) would now speak at length, but then we reflected on his (peace and blessings be upon him) words and found that he (peace and blessings be upon him) had gathered the whole matter in them.
Hadith Referenceالمعجم الكبير للطبراني / باب الصاد / 7647