The Prophet (peace and blessings be upon him) said, "After every prayer, if anyone:
1-GLORIFIES Allah (by saying Subhaan-Allah) Thirty Three times, and
2- PRAISES Allah (by saying Al-hamdu-lillah) Thirty Three times, and
3- DECLARES HIS GREATNESS (by saying Allahu-Akbar) Thirty Three times,
4- and says (once), to complete a hundred,
"No one has the right to be worshipped but Allah alone, Who has no partner; to Him belongs all sovereignty, and to Him is due all praise; and He has power over all things", [In Arabic: "Laa Ilaaha Illallaahu, Wah-dahu Laa Shareeka Lahoo, Lahul Mulku, Wa Lahul Hamdu, Wa Huwa 'Alaa Kulli Shay-in Qadeer."],
His sins will be forgiven even if these are as abundant as the foam of the sea.