Muwatta Imam Malik Book of Purity, Hadith 89

Yahya related to me from Malik from Nafi that Abdullah ibn Umar used to sweat in a garment while he was junub and then pray with it on.

وَحَدَّثَنِي عَنْ مَالِكٍ، عَنْ نَافِعٍ، أَنَّ عَبْدَ اللَّهِ بْنَ عُمَرَ، كَانَ يَعْرَقُ فِي الثَّوْبِ وَهُوَ جُنُبٌ ثُمَّ يُصَلِّي فِيهِ .