Hadith 153

(حديث مرفوع) حَدَّثَنَا الْحَسَنُ ، حَدَّثَنَا ابْنُ لَهِيعَةَ ، حَدَّثَنَا أَبُو الزُّبَيْرِ ، عَنْ جَابِرٍ ، أَنَّ عُمَرَ بْنَ الْخَطَّابِ أَخْبَرَهُ : أَنّ 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 .
It is narrated from Sayyiduna Umar (may Allah be pleased with him) that once the Prophet (peace and blessings be upon him) saw a man who was performing ablution for the Zuhr prayer. While making ablution, he left a spot on the back of his foot the size of a fingernail, meaning he did not wash it or water did not reach there. The Prophet (peace and blessings be upon him) saw him and said, "Go and perform ablution properly." So he went, performed ablution again, and offered the prayer.
Hadith Reference مسند احمد / مسند الخلفاء الراشدين / 153
Hadith Grading حکم دارالسلام: حديث صحيح، ابن لهيعة قد توبع. م: 243