Abdullah bin Abbas (may Allah be pleased with them both) narrates that the Prophet Muhammad (peace be upon him) said: "Whoever claims to have seen in a dream that which he did not see (i.e., whoever narrates a false dream), he will be made to tie a knot between two grains of barley on the Day of Resurrection, and whoever eavesdrops on people's conversations while they dislike it, molten lead will be poured into his ears on the Day of Resurrection."