Musnad Ahmad Hadith 10085

It is narrated from Abu Hurairah (may Allah be pleased with him) that once, while I was in a state of impurity, I met the Noble Prophet (ﷺ). I continued walking with the Noble Prophet (ﷺ) until he sat down at a place. Taking the opportunity, I slipped away from behind and went to my tent, performed ghusl (ritual bath), and then returned to the presence of the Prophet. The Noble Prophet (ﷺ) was still sitting there. Upon seeing me, he asked, "Where did you go?" I replied, "When I met you, I was in a state of impurity. I did not feel it appropriate to sit with you in that state, so I left and performed ghusl (and have now come back to your service)." The Noble Prophet (ﷺ) said, "A believer does not become impure."