SINCEREST GRATITUDE H 1183 "The Messenger of Allah, praise and peace be upon him, stood so long during his voluntary prayer at night that the skin of his feet would crack; so Lady Ayesha, may Allah be pleased with her, asked, 'O Messenger of Allah, praise and peace be upon him, why do you stand so long in prayer when Allah has forgiven you in the past and in future?' He answered, 'Could it not be that I would love to be a thankful worshiper.'" R 1183 Bukhari and Muslim with a chain up to Lady Ayesha, wife of the Prophet, may Allah be pleased with her, Mother of Believers related that the Messenger of Allah, praise and peace be upon him, said this.
1160- وعن عائشة رضي الله عنها ، قالت : كَانَ النبيُّ صلى الله عليه وآله وسلم يَقومُ مِنَ اللَّيْلِ حَتَّى تَتَفطَّرَ قَدَمَاهُ ، فَقُلْتُ لَهُ : لِمَ تَصْنَعُ هَذَا ، يَا رَسُولَ الله ، وَقَدْ غُفِرَ لَكَ مَا تَقَدَّمَ مِنْ ذَنْبِكَ وَمَا تَأخَّرَ ؟ قَالَ : "أفَلاَ أكُونُ عَبْداً شَكُوراً!" متفقٌ عَلَيْهِ . وَعَن المُغِيرَةِ بن شُعبة نَحْوهُ متفقٌ عَلَيْهِ .