حَدَّثَنَا الْحَسَنُ حَدَّثَنَا ابْنُ لَهِيعَةَ حَدَّثَنَا أَبُو الزُّبَيْرِ عَنْ جَابِرٍ أَنَّ عُمَرَ بْنَ الْخَطَّابِ رَضِيَ اللَّهُ عَنْهُ أَخْبَرَهُ أَنَّ رَسُولَ اللَّهِ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ رَأَى رَجُلًا تَوَضَّأَ لِصَلَاةِ الظُّهْرِ فَتَرَكَ مَوْضِعَ ظُفُرٍ عَلَى ظَهْرِ قَدَمِهِ فَأَبْصَرَهُ رَسُولُ اللَّهِ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ فَقَالَ ارْجِعْ فَأَحْسِنْ وُضُوءَكَ فَرَجَعَ فَتَوَضَّأَ ثُمَّ صَلَّى
مسند امام احمد بن حنبل · Hadith 153
It was narrated from Jabir that 'Umar bin al-Khattab (RA) told him that the Messenger of Allah saw a man doing wudoo' to pray Zuhr, and he missed a spot the size of a toenail. The Messenger of Allah saw him and said: "Go back and do your wudoo' properly." So he went back and did wudoo', then he prayed.
Translated by Dr. Muhammad Muhsin Khan · Reviewed by Islamic University of Madinah · Published March 2020