It is narrated from Sayyiduna Wathilah bin al-Asqa' (may Allah be pleased with him) that he heard the Messenger of Allah (peace and blessings be upon him) say: "The greatest lie is that someone fabricates against me what I did not say, or that a man ascribes himself to someone other than his father, or makes his eyes see in a dream what they did not see."
Hadith Referenceالمعجم الكبير للطبراني / باب الواو / 18399