It is narrated from Sayyiduna Abdullah bin Abbas (may Allah be pleased with them both) that the Prophet (peace and blessings be upon him) said: "Whoever listens to the talk of people while they dislike it, molten lead will be poured into his ear on the Day of Resurrection. And whoever claims to have seen with his eyes in a dream something he did not see will be charged (with an impossible task) to tie a barley grain finely."
Hadith Referenceالمعجم الكبير للطبراني / باب العين / 11587