Mishkat al-Masabih — Hadith #48193

And on the authority of Zaid bin Thabit, he said: We were commanded to say “Tasbih” thirty-three times after every prayer, “thank God” thirty-three times, and “to say “Allahu Akbar” thirty-four times. Then a man came in a dream. From the Ansar, and it was said to him: The Messenger of God, may God bless him and grant him peace, commanded you to say “Tasbih” at the end of every prayer, such-and-such. He said: Al-Ansari said in his dream, “Yes.” He said, “So make it twenty-five and twenty-five, and make the Tahlil in it.” And when the morning came tomorrow, the Prophet, may God bless him and grant him peace So he informed him, and the Messenger of God, may God bless him and grant him peace, said: “So do it.” Narrated by Ahmad, Al-Nasa’i and Al-Darimi