John Gill Commentary Deuteronomy 6:15

"for Jehovah thy God in the midst of thee is a jealous God; lest the anger of Jehovah thy God be kindled against thee, and he destroy thee from off the face of the earth." — Deuteronomy 6:15 (ASV)

For the Lord your God is a jealous God among you
He was near to them, in the midst of them, his tabernacle being placed between their camps; and was a God jealous of his honour and glory in matters of worship, and would resent any affront given him in that way:

lest the anger of the Lord your God be kindled against you ;
there being nothing more apt to stir up his wrath than idolatry:

and destroy you from off the face of the earth ;
suffer them to be carried captive out of their own land, and to be scattered among the nations of the world, and be utterly destroyed.