It is narrated from Hazrat Abu Huraira (may Allah be pleased with him) that I heard the Noble Prophet (peace and blessings be upon him) saying: When any one of you offers prayer and then remains seated on his prayer mat, the angels continuously say: O Allah, forgive him. O Allah, have mercy on him, as long as he does not lose his ablution or leave from there.
Hadith Referenceمسند احمد / مسند المكثرين من الصحابة / 10499
Hadith Gradingحکم دارالسلام:حديث صحيح، خ: 477، م: 649، محمد بن إسحاق وإن كان مدلسا وقد عنعنه، لكنه توبع