They helped every one his neighbor; and every one said to his brother, Be of good courage.…
The sarcasm consists in making the idolaters dependent upon idols which are themselves dependent upon common workmen and the most trivial mechanical operations for their form and their stability. Hence the particular enumeration of the different artificers employed in the manufacture of these deities. The last clause implies that the strength of the idol is not in itself, but in the nails that keep it in its place, or hold its parts together.
(J. A. Alexander.)
Parallel VersesKJV: They helped every one his neighbour; and every one said to his brother, Be of good courage.