Sunan Ibn Majah Book 33, Hadith 157
"The Messenger of Allah (ﷺ) said to me: 'You should recite Subhan-Allah, wal-Hamdu-Lillah, wa la ilahah illallah, wa Allahu Akbar (Glory is to Allah, praise is to Allah, none has the right to be worshiped but Allah, and Allah is the Most Great), for it sheds sins like the tree sheds its leaves.'"
the Messenger of Allah (ﷺ) said: "Whoever says: Subhan Allahi wa bi hamdihi (Glory and praise is to Allah) one hundred times, his sins will be forgiven even if they were like the foam of the sea.'"
"We used to count that the Messenger of Allah (ﷺ) said one hundred times in a gathering: 'Rabbighfirli wa tub `alayya innaka Antat-Tawwabur-Rahim (O Allah forgive me and accept my repentance, for You are the Accepter of repentance, the Most Merciful).'"