Musnad Ahmad Hadith 22082

Mu'adh (may Allah be pleased with him) says that once, at night, I went out in search of the Noble Prophet (ﷺ). I was told that the Noble Prophet (ﷺ) had gone out. Whoever I passed by would say that the Noble Prophet (ﷺ) just passed by here, until I found him standing at a place, performing prayer. I also stood behind him. The Noble Prophet (ﷺ) started the prayer and kept it long, until when he finished his prayer with salam, I submitted, "O Messenger of Allah! Tonight you performed a very long prayer." The Noble Prophet (ﷺ) said, "Yes! This was a prayer of encouragement and warning. In this prayer, I asked my Lord for three things, out of which He granted me two and denied me one. I requested my Lord not to destroy my ummah by drowning in the sea, and He accepted my request. Then I requested Him not to impose an external enemy upon them, so He accepted this request as well. Then I requested my Lord not to divide us into different sects, but He did not accept this request."