Muwatta Malik 73

وَحَدَّثَنِي عَنْ مَالِكٍ، عَنْ نَافِعٍ، أَنَّ عَبْدَ اللَّهِ بْنَ عُمَرَ، بَالَ فِي السُّوقِ ثُمَّ تَوَضَّأَ فَغَسَلَ وَجْهَهُ وَيَدَيْهِ وَمَسَحَ رَأْسَهُ ثُمَّ دُعِيَ لِجَنَازَةٍ لِيُصَلِّيَ عَلَيْهَا حِينَ دَخَلَ الْمَسْجِدَ فَمَسَحَ عَلَى خُفَّيْهِ ثُمَّ صَلَّى عَلَيْهَا ‏.‏

Yahya related to me from Malik from Nafi that Abdullah ibn Umar urinated in the market place and then did wudu, washing his face and hands and wiping his head. Then as soon as he had come into the mosque, he was called to pray over a dead person, so he wiped over his leather socks and prayed

Reference

Muwatta Malik 73

In-book

Book 2, Hadith 42