It is narrated from Sayyiduna Ibn Abbas (may Allah be pleased with them both) that the Messenger of Allah (peace and blessings be upon him) said: "Whoever listens (secretly) to the talk of people, molten lead will be poured into his ears; and whoever fabricates a dream will be required to tie a knot between two grains of barley, and he will never be able to do it."
Hadith Referenceالمعجم الكبير للطبراني / باب العين / 11834