Sayyiduna Anas bin Malik (may Allah be pleased with him) said: The Prophet (peace and blessings be upon him) entered the prayer and said the takbir, and we also said the takbir with him (peace and blessings be upon him). Then he (peace and blessings be upon him) gestured to the people: "Remain as you are." We remained standing, waiting for the Prophet (peace and blessings be upon him), until he (peace and blessings be upon him) came; he (peace and blessings be upon him) had taken a ritual bath (ghusl) and drops were flowing from his (peace and blessings be upon him) head.
Abd al-Wahhab bin Ata' contradicted him and narrated it from Sa'id, from Qatadah, from Bakr bin Abdullah al-Muzani, from the Prophet (peace and blessings be upon him) as mursal.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الصلاة / 4071