Indeed the wages of the laborers who mowed your fields, which you kept back by fraud, cry out; and the cries of the reapers have reached the ears of the Lord of Sabaoth. You have lived on the earth in pleasure and luxury; you have fattened your hearts as in a day of slaughter. You have condemned, you have murdered the just; he does not resist you.
As we read through the Old Testament we see that God had given commands to all landowners. During harvest time they were not to harvest the corners of their fields. In addition, they were only allowed to go through their field one time. Landowners could not go through their fields a second or third time to ensure they got every last piece of the harvest. God had done this for the overall good of society. God’s commands created a mechanism whereby the poor and needy by their own labor could go into the fields and harvest food to feed themselves and their families. However the wicked landowners in their greed, those who were in rebellion against God were taking everything for themselves and ignoring God’s commandments. And if that wasn’t enough when the harvesters finished the landowner would defraud them. The landowners would do what they could in order to avoid paying their wages for the day. Both of these acts were expressly forbidden by God, especially in light that God had given them the land.
The land was not theirs to begin with, God had taken it from the Canaanites and given it to Israel. If this wasn’t bad enough the landowners were bribing the court system to steal what little land the poor had. They did so in order to gain more for themselves as they lived extravagant lifestyles. And what James tells them through the inspiration of the Holy Spirit, is that in the end, the wicked landowners are like lambs heading to the slaughter. God tells them in reality they’re just fattening themselves for the day of slaughter. A time when God will pour out His wrath against them. In their wicked actions the landowners had murdered the just and stolen from the poor. And James is not referring to actual murder, but rather by defrauding the poor, they brought about the destruction of peoples lives. James is therefore reminding them that God not only sees their actions, but God also knows the wicked intent of their hearts. In addition the landowners were ignorant to the fact that the prayers of the innocent come up before God asking for justice. And we know from passages elsewhere in the New Testament that the prayers of the saints come up before the very throne of God.