Charles Ellicott Commentary Jeremiah 23:32

"Behold, I am against them that prophesy lying dreams, saith Jehovah, and do tell them, and cause my people to err by their lies, and by their vain boasting: yet I sent them not, nor commanded them; neither do they profit this people at all, saith Jehovah." — Jeremiah 23:32 (ASV)

False dreams.—The words may mean either actual dreams, which have nothing corresponding to them in the world of facts, or dreams which are not really such, but simply, as in Jeremiah 23:31, the form in which the deceiver seeks to carry out his plans.

By their lightness.—The Hebrew word is the same in meaning as “unstable as water” (Genesis 49:4), the “light persons” (Judges 9:4; Zephaniah 3:4), and points primarily to the gushing or spurting forth of water. Here it points to what we may call the “babbling” of the false prophets. We are almost reminded of the words in which an English poet describes a hollow and pretentious eloquence as poured out—

“In one weak, washy, everlasting flood.”

Therefore ...—Better, simply, and they shall not profit.