Sahih Al Bukhari 1: Chapter 2, Hadith 20

(20) The statement of the Prophet I know Allah تعالیٰ better, than all of you do.”

Narrated 'Aisha: Whenever Allah's Apostle ordered the Muslims to do something, he used to order them deeds which were easy for them to do, (according to their strength and endurance). They said, O Allah's Apostle! We are not like you. Allah has forgiven your past and future sins. So Allah's Apostle became angry and it was apparent on his face. He said, I am the most Allah fearing, and know Allah better than all of you do.

حَدَّثَنَا مُحَمَّدُ بْنُ سَلَامٍ، ‏‏‏‏‏‏قَالَ:‏‏‏‏ أَخْبَرَنَا عَبْدَةُ، ‏‏‏‏‏‏عَنْ هِشَامٍ، ‏‏‏‏‏‏عَنْ أَبِيهِ، ‏‏‏‏‏‏عَنْ عَائِشَةَ، ‏‏‏‏‏‏قَالَتْ:‏‏‏‏ "كَانَ رَسُولُ اللَّهِ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ إِذَا أَمَرَهُمْ، ‏‏‏‏‏‏أَمَرَهُمْ مِنَ الْأَعْمَالِ بِمَا يُطِيقُونَ، ‏‏‏‏‏‏قَالُوا:‏‏‏‏ إِنَّا لَسْنَا كَهَيْئَتِكَ يَا رَسُولَ اللَّهِ، ‏‏‏‏‏‏إِنَّ اللَّهَ قَدْ غَفَرَ لَكَ مَا تَقَدَّمَ مِنْ ذَنْبِكَ وَمَا تَأَخَّرَ، ‏‏‏‏‏‏فَيَغْضَبُ حَتَّى يُعْرَفَ الْغَضَبُ فِي وَجْهِهِ، ‏‏‏‏‏‏ثُمَّ يَقُولُ:‏‏‏‏ إِنَّ أَتْقَاكُمْ وَأَعْلَمَكُمْ بِاللَّهِ أَنَا".

REFERENCE:

Sahih Al Bukhari 1: Chapter 2, Hadith 20