´It was narrated that Abu Hurairah said:` "The Messenger of Allah (ﷺ) said: 'Whoever says the tasbih one hundred times following the morning prayer, and the tahlil one hundred times, he will be forgiven his sins even if they are like the foam of the sea.'"
Hadith Referenceسنن نسائي / كتاب السهو / 1355
Hadith Gradingالألبانی:صحيح الإسناد | زبیر علی زئی:ضعيف، إسناده ضعيف، أبو الزبير عنعن. انوار الصحيفه، صفحه نمبر 331