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: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)?
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 " .
Muslim
Characteristics of the Day of Judgment, Paradise, and Hell • Hadith 79