"idols give false messages." Zechariah is not suggesting that idols actually speak. He is referring to the messages people say they hear from idols. The UDB makes this explicit.
It is implied that they know these dreams are false. This can be made explicit. AT: "diviners lie about their dreams in order to deceive people" (See: [[rc://en/ta/man/translate/figs-explicit]])
# empty comfort
This refers to words that sooth temporarily, but do not provide any longterm help.
# they wander like sheep
The people who do not have true prophets who tell the truth are spoken of as sheep who do not have a shepherd to tell them where to go. AT: "the people who listen to the false prophets are like sheep who do not know which way to go" (See: [[rc://en/ta/man/translate/figs-simile]])
# they ... suffer because there is no shepherd
The people who do not have true prophets are spoken of as sheep who suffer because they do not have a shepherd to tell them where to go. AT: "the people who listen to the false prophets ... are suffering like sheep who do not have a shepherd to guide them" (See: [[rc://en/ta/man/translate/figs-simile]])