The Messenger of Allah ﷺ said, "Whoever sees me in a dream has truly seen me, for Satan cannot take on my form."
حدثنا وكيع عن سفيان عن أبي حصين عن أبي صالح
قال رسول الله ﷺ من رآني في المنام فقد رآني في اليقظة فإن الشيطان لا يتمثل على صورتي
Its isnad is sahih. Abu Husayn, with a fatha on the ha, is Uthman bin Asim Asadi. This hadith belongs to the musnad of Abu Hurairah, not the musnad of Ibn Masud, and it was mentioned only for the sake of the hadith that follows it. This hadith of Abu Hurairah was narrated by the two Shaykhs and by Ibn Majah, as noted in Sharh Tirmidhi 3:249, and see also 2525, 3410, 3559.