Jeremiah 10:5
They are upright as the palm tree, but speak not: they must needs be borne, because they cannot go. Be not afraid of them; for they cannot do evil, neither also is it in them to do good. They are upright as the palm tree, but speak not: they must needs be borne, because they cannot go. Be not afraid of them; for they cannot do evil, neither also is it in them to do good.
Idols are lifeless and powerless. Their uprightness as the palm tree means they stand erect in human-like form yet remain inanimate. Their inability to speak shows they have no living voice or communication. Their inability to move means they must be carried from place to place because they cannot go of themselves.
To do neither evil nor good means they can neither harm people nor help, bless, or benefit them, giving no blessing and doing people no good. This helplessness stands in contrast to the living God, who made the world and rules over it. Even though these gods could do no good, their worshippers trusted in them and acted according to that trust.