The Messenger of Allah ﷺ began the dawn prayer, then gestured with his hand for them to stay in their places. He went away and returned with water dripping from his head, and he led them in prayer.
أن رسول الله ﷺ دخل في صلاة الفجر فأوما بيده: أن مكانكم، ثم جاء ورأسه يقطر فصلى بهم.
It was narrated by Abu Dawud (233), Ahmad (20420), Ibn Khuzayma (1629), Ibn Hibban (2235), and Bayhaqi (2/397), all of them through Hammad bin Salama, from Ziyad Alam, from Hasan, from Abu Bakra. He related it. The wording given is that of Abu Dawud. Ahmad's wording is, "He opened the prayer and said the takbir, then gestured to them, 'Stay where you are,' then went in, then came out with his head dripping, and led them in prayer. When he finished the prayer he said, 'I am only a man, and I had been in a state of major impurity.'"Hasan here is the well known imam, and he is a mudallis who used ambiguous transmission wording (anaa). However, Bukhari, in his Sahih, narrated several hadiths in which he confirmed Hasan's direct hearing from Abu Bakra, just as he also narrated several hadiths with the ambiguous wording, because he had established that Hasan's hearing from those he used ambiguous wording for was confirmed, and this is one such case.It was also narrated from Abu Hurairah, who said, "The Prophet ﷺ came out for the prayer, and when he said the takbir he turned away and gestured to them," meaning "stay as you are," "then he went out and washed himself, then came with his head dripping, and led them in prayer. When he had prayed he said, 'I had been in a state of major impurity and forgot to wash.'"This was narrated by Ibn Majah (1220), Ahmad (9786), Daraqutni (1362), and Bayhaqi (2/97), all of them through Usama bin Zayd, from Abdullah bin Yazid the freedman of Aswad bin Sufyan, from Ibn Turban, from Abu Hurairah. He related it.Usama bin Zayd here is Laythi, who is described as making errors, so perhaps his statement "when he said the takbir he turned away" is one of his errors, unless it is understood as two separate hadiths, as Nawawi and others have said. Abu Hurairah narrated a great many hadiths, so it is not unlikely that he had two hadiths, one as found in the Sahihayn, and the other as in the hadith of Abu Bakra.It was also narrated from Anas, who said, "The Messenger of Allah ﷺ entered into his prayer and said the takbir, and we said the takbir with him, then he gestured to the people, 'Stay as you are.' So we remained standing until the Messenger of Allah ﷺ came to us having washed himself, with his head dripping."This was narrated by Tabarani in Awsat (3947), Daraqutni (1362), and Bayhaqi (2/399), all of them through Ubaydullah bin Muaz, who said, my father narrated to us, who said, Saeed bin Abu Aruba narrated to us, from Qatada, from Anas bin Malik, who said, and he related it. Its narrators are trustworthy. However, Daraqutni said, Abdul-Wahhab Khaffaf differed from him, narrating it from Saeed, from Qatada, from Bakr bin Abdullah Muzani, that the Prophet ﷺ entered into his prayer and said the takbir, and those behind him said the takbir. He related the hadith. Abdul-Wahhab said, "This is what we adopt."This is further strengthened by what Abu Dawud mentioned, saying, "It was also narrated by Ayub, Ibn Awn, and Hisham, from Muhammad" meaning Ibn Sirin, "from the Prophet ﷺ, who said, 'He said the takbir, then gestured to the people to sit, and went and washed himself.'" Likewise, Malik narrated it from Ismail bin Abu Hakeem, from Ata bin Yasar, that the Messenger of Allah ﷺ said the takbir in his prayer.Abu Dawud then said, "Likewise, Muslim bin Ibrahim narrated to us, Aban narrated to us, from Yahya, from Rabi bin Muhammad, from the Prophet ﷺ, that he said the takbir." End of quote.Related in meaning to this is also what was narrated from Ali bin Abu Talib, who said, "While we were with the Messenger of Allah ﷺ praying, he turned away while we remained standing, then he came forward with his head dripping and led us in the prayer." He then related the story.This was narrated by Ahmad (668) from Hasan bin Musa, who said, Ibn Lahia narrated to us, who said, Harith bin Yazid narrated to us, from Abdullah bin Zurayr Ghafiqi, from Ali. He related it. There is well known discussion regarding Ibn Lahia.