عَنْ أَنَسِ بْنِ مَالِكٍ رضى الله عنه
قَالَ: «كَانَ رَسُولُ اَللَّهِ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ: إِذَا دَخَلَ اَلْخَلَاءَ وَضَعَ خَاتَمَهُ»
The Messenger of Allah (sallallahu alayhi wa sallam) used to remove his ring when entering the lavatory.
Bulugh al-Maram 105, Book 1, The Book of Purification, Hadith 105. 1 min read