Sayyiduna Zaid bin Thabit (may Allah be pleased with him) says: We were commanded that after every prayer we should say Subhan Allah thirty-three times, Alhamdulillah thirty-three times, and Allahu Akbar thirty-four times. But an Ansari saw a dream, and in the dream he was asked: Did the Messenger of Allah (peace and blessings be upon him) command you to say Subhan Allah (and the other remembrances) this many times after every prayer? He replied in the dream: Yes. So the one who came in the dream said: Do it twenty-five times each, and add twenty-five times La ilaha illallah. When morning came, he went to the Noble Prophet (peace and blessings be upon him) and informed him of this dream. The Messenger of Allah (peace and blessings be upon him) said: Do it like that.