Sahih Muslim 2820
Sahih Muslim · Book 52: Characteristics of the Day of Judgment, Paradise, and Hell · Doing A Lot Of Good Deeds And Striving Hard In Worship
A'isha reported that when Allah's Messenger (ﷺ) occupied himself in prayer, he observed such a (long) qiyam (posture of standing in prayer) that his feet were swollen. A'isha said:
حَدَّثَنَا هَارُونُ بْنُ مَعْرُوفٍ ، وَهَارُونُ بْنُ سَعِيدٍ الأَيْلِيُّ ، قَالاَ حَدَّثَنَا ابْنُ وَهْبٍ ، أَخْبَرَنِي أَبُو صَخْرٍ ، عَنِ ابْنِ قُسَيْطٍ ، عَنْ عُرْوَةَ بْنِ الزُّبَيْرِ ، عَنْ عَائِشَةَ ، قَالَتْ كَانَ رَسُولُ اللَّهِ صلى الله عليه وسلم إِذَا صَلَّى قَامَ حَتَّى تَفَطَّرَ رِجْلاَهُ قَالَتْ عَائِشَةُ يَا رَسُولَ اللَّهِ أَتَصْنَعُ هَذَا وَقَدْ غُفِرَ لَكَ مَا تَقَدَّمَ مِنْ ذَنْبِكَ وَمَا تَأَخَّرَ فَقَالَ " يَا عَائِشَةُ أَفَلاَ أَكُونُ عَبْدًا شَكُورًا " .
Allah's Messenger you do this (in spite of the fact) that your earlier and later sins have been pardoned for you? Thereupon, he said. A'isha should I not prove myself to be a thanksgiving servant (of Allah)?