Hadith 134

(حديث مرفوع) حَدَّثَنَا مُوسَى بْنُ دَاوُدَ ، حَدَّثَنَا ابْنُ لَهِيعَةَ ، عَنْ أَبِي الزُّبَيْرِ ، عَنْ جَابِرٍ ، أَنَّ عُمَرَ بْنَ الْخَطَّابِ أَخْبَرَهُ : أَنَّهُ رَأَى رَجُلًا تَوَضَّأَ لِلصَّلَاةِ ، فَتَرَكَ مَوْضِعَ ظُفُرٍ عَلَى ظَهْرِ قَدَمِهِ ، فَأَبْصَرَهُ النَّبِيُّ 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 he saw a person who was performing ablution for prayer, and while doing so, he left an area 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) also 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 / 134
Hadith Grading حکم دارالسلام: حديث صحيح، عبدالله ابن لهيعة- وإن كان سيء الحفظ - توبع