John Calvin Commentary Deuteronomy 6:14

"Ye shall not go after other gods, of the gods of the peoples that are round about you;" — Deuteronomy 6:14 (ASV)

You shall not go after. In this passage, Moses commands the people not to turn away from the simple service of God, although examples of superstition may appear before them on every side. For this was a very destructive temptation: no one could be found anywhere who subscribed to the doctrine of the Law, although the various nations had some religion, or at least the name of it, existing among them. Therefore, since these various forms of worship were so many temptations to forsake the right way, it was necessary to guard against the danger in good time and to establish the authority of the One God, so that the Jews would have the courage to despise the common belief of all the Gentiles.

A threat is added that vengeance would not be far off if they were to fall away into these superstitions, since God is a jealous God, and dwelling among them. As for the former epithet, I will say more under the Second Commandment.

Meanwhile, let my readers observe that God is called jealous because He permits no rivalry that might detract from His glory, nor does He allow the service due to Him alone to be transferred elsewhere. When He reminds the people that He dwells among them, it is partly to inspire terror because of His presence and partly to rebuke their ingratitude indirectly, if they should forsake Him and seek for themselves gods who are far away.