أَخْبَرَنَا مُحَمَّدُ بْنُ عَبْدِ الأَعْلَى، أَنْبَأَنَا أُمَيَّةُ بْنُ خَالِدٍ، حَدَّثَنَا شُعْبَةُ، أَنَّ مُخَارِقًا، أَخْبَرَهُمْ عَنْ طَارِقِ بْنِ شِهَابٍ، أَنَّ رَجُلاً، أَجْنَبَ فَلَمْ يُصَلِّ فَأَتَى النَّبِيَّ صلى الله عليه وسلم فَذَكَرَ ذَلِكَ لَهُ فَقَالَ ‏"‏ أَصَبْتَ ‏"‏ ‏.‏ فَأَجْنَبَ رَجُلٌ آخَرُ فَتَيَمَّمَ وَصَلَّى فَأَتَاهُ فَقَالَ نَحْوًا مِمَّا قَالَ لِلآخَرِ يَعْنِي ‏"‏ أَصَبْتَ ‏"‏ ‏.‏

It was narrated from Tariq bin Shaihab that a man became Junub and did not pray. He came to the Prophet (PBUH) and told him about that, and he said: "You did the right thing." Then another man became Junub so he performed Tayammum and prayed. He came (to the Prophet (PBUH)) who said to him what he had said to the other man- meaning, "You did the right thing." Translation Not Available

Book reference: Sunan An Nisai Book 4 Hadith 434b
Web reference: Sunan An Nisai Volume 1 Book 4 Hadith 435