"I went out with the Messenger of Allah (ﷺ) to an isolated area, and when he wanted to relieve himself he moved far away."
Sunan an-Nasa'i Book 1, Hadith 16
← Previous Hadith "Trim the mustache and let the beard grow."

Sunan an-Nasa'i Book 1, Hadith 15 Next Hadith → "Bring me (water for) Wudu'." So I brought him (water for) Wudu', and he performed Wudu' and wiped over his Khuffs. The Shaikh said: "Isma'il (one of the narrators) is Ibn Ja'far bin Abi Kathir Al-Qari.

Meaning the author, and it appears that Ibn As-Sunni who heard the text, said this.

Sunan an-Nasa'i Book 1, Hadith 17