“We were ordered to say the Tasbīḥ at the end of every Salat thirty-three times, and to say the Takbīr thirty-four times.” He said: “Then a man from the Ansar had a dream in which someone said: ‘The Messenger of Allah (ﷺ) ordered you to say the Tasbīḥ at the end of every Salat thirty-three times, and to say the Taḥmīd thirty-three times, and to say the Takbīr thirty-four times?’ He said: ‘Yes.’ He said: ‘Then make them twenty-five and add the Tahlīl (saying Lā ilāha illallāh) to them.’ The next day he went to the Prophet (ﷺ) and informed him, so he said: “Do it.”
Jami` at-Tirmidhi Book 48, Hadith 44