Behold, the wages of the laborers who mowed your fields, which you kept back by fraud, are crying out against you, and the cries of the harvesters have reached the ears of the Lord of hosts.
Our God is a God who hears. When you consider that the God of the universe, who created all things, takes the time to listen to the cries of the people whom he has created it is truly staggering. We are told to cast all our cares on him because he cares for us. We know that in Jesus Christ we see God coming to earth and dwelling with mankind. What an amazing mystery!
Here James reminds the ungodly rich that God hears. Who does God hear? God hears the cries of those who have been defrauded by these rich field owners. These laborers were not paid all of what they earned. This is an example of injustice. God is a just God. He will not allow sin to go unpunished.
We become very frustrated when we feel that we have been treated unjustly. Perhaps we have worked for someone who did not pay us what we were promised. Maybe we have had possessions stolen from us. It is possible that we have had a relationship that ended with people assuming evil of us, and it is without warrant. God sees the injustice. And when we cry out to him he hears.
In the last part of the verse James describes the "ears of the Lord of Hosts." This title given to God is found often in the Old Testament. It is a military description, meaning "captain of the armies." Needless to say, you would not want the Lord of Hosts coming against you. If you are defrauding others God is coming against you.
Be careful that you deal with others fairly. God hears the cries of those whom we defraud. If you have been treated with injustice cry out to the one who hears, and cares.