The Prophet ﷺ said, "A true dream is one of seventy parts of prophethood."
حدثنا يحيى عن عبيد الله أخبرني نافع
عن النبي ﷺ قال الرؤيا جزء من سبعين جزءا من النبوة
Its isnad is sahih. Muslim reported it (2:201) via Abu Usama and Ibn Numayr, and via Yahya, all three from Ubaydullah, and via Layth bin Saad and Dahhak bin Uthman, both of them from Nafi. Muslim's wording is "the righteous dream," and the word "righteous" was not mentioned here in the two original manuscripts, although its intent is clearly understood. It was written in the margin of manuscript K, but without the mark indicating correction, so I have not included it in the body of the hadith. A similar hadith with a sahih isnad has already passed from the narration of Ibn Abbas [2896].