It was narrated from Al-Mughirah that the Prophet (ﷺ) performed Wudu', and he wiped the forehead, the 'Imamah, and over the Khuff. (Another chain)
Sunan an-Nasa'i Book 1, Hadith 107
← Previous Hadith "I saw the Messenger of Allah (ﷺ) wiping over the Khimar and Khuff."

Sunan an-Nasa'i Book 1, Hadith 106 Next Hadith → "The Messenger of Allah (ﷺ) stayed behind, and I stayed with him. When he had relieved himself he said: 'Do you have any water with you?' I brought some water to him, and he washed his hands and face, then he started trying to uncover his arms, but the sleeves of his Jubbah were too tight, so he threw it over his shoulders and washed his arms and wiped over his forehead and 'Imamah, and over his Khuff."

Sunan an-Nasa'i Book 1, Hadith 108