William Burkitt on James 4:1

The Jews, to whom St. James directed this epistle, had at that time great wars and fightings, not only with their neighbours, but even among themselves: in every city there were wars and fightings among them.

Now, the apostle here puts it to their consciences to tell and declare whence these animosities and contentions, those wars and fightings, did proceed; come they not hence, even from your lusts?

Plainly intimating, that the cause of all civil dissentions are men's corruptions: War stirs first within, before it breaks forth without; were there not a fight in ourselves, there would be no fighting with others. Lust within is the make-bait in all societies and communities without. Pride and covetousness, envy and ambition, make men injurious to one another; worldly and sensual lusts first war in ourselves, before they disturb the common peace.