It is narrated from Hazrat Abu Huraira (may Allah be pleased with him) that the Noble Prophet (peace and blessings be upon him) said: Whoever regularly performs two rak'ahs of Duha prayer, all his sins will be forgiven, even if they are as much as the foam of the sea.
Hadith Referenceمسند احمد / مسند المكثرين من الصحابة / 10447
Hadith Gradingحکم دارالسلام:إسناده ضعيف لضعف النهاس، وشداد لم يسمع من ابي هريره