Musnad Ahmad 5:137

Abdullah ibn al-Walid and Abu Ahmad al-Zubayri narrated to us, they said: Sufyan narrated to us, from Abd al-A’la, from Abu Abd al-Rahman, from Ali ibn Abi Talib—Sufyan said: I do not know it except that he attributed it to the Prophet—he said: "Whoever lies about a dream he has seen, he will be tasked on the Day of Resurrection to tie a knot in a barley grain." Abu Ahmad said: He said, "I believe it is from the Prophet, may Allah bless him and grant him peace."