Musnad Ahmad 30:125

Al-Walid narrated to us, Al-Awza'i narrated to us, Hassan bin 'Atiyyah narrated to me, Muhammad bin Abi 'Aishah narrated to me, from Abu Hurairah, that he narrated to them: That Abu Dharr said: "O Messenger of Allah, the wealthy have taken away the rewards; they pray as we pray, and they fast as we fast, and they have surplus wealth which they give in charity, while we have nothing to give in charity." The Messenger of Allah (ﷺ) said: "Shall I not guide you to words, if you act upon them, you will catch up with those who have surpassed you, and no one will overtake you except those who do the same as your deeds?" He said: "Yes, O Messenger of Allah." He said: "You say 'Allahu Akbar' (God is the Greatest) thirty-three times after every prayer, and you say 'Subhan Allah' (Glory be to Allah) thirty-three times, and you say 'Alhamdulillah' (Praise be to Allah) thirty-three times, and you conclude it with 'La ilaha illallah, wahdahu la sharika lah, lahul-mulku wa lahul-hamdu, wa huwa 'ala kulli shay'in qadir' (There is no god but Allah, alone, with no partner, to Him belongs the dominion, and to Him belongs the praise, and He is capable of all things)."