It is narrated from Hazrat Abu Huraira (may Allah be pleased with him) that the Holy Prophet (peace and blessings be upon him) said: O Allah, I seek from You a promise which You will never break with me. If, being human, I have caused any harm to a Muslim, or spoken harshly to him, or struck him, or cursed him, then make it a source of mercy, purification, and nearness to You for that person on the Day of Judgment.
Hadith Referenceمسند احمد / مسند المكثرين من الصحابة / 9074
Hadith Gradingحکم دارالسلام:حديث صحيح، خ: 6361، م: 2601، وهذا إسناد ضعيف، ابن لهيعة سيئ الحفظ