the cause

Exodus 21:20, 21, 26, 27
If a man strikes his male or female servant with a rod, and the servant dies by his hand, he shall surely be punished. . . .

Leviticus 25:43, 46
You are not to rule over them harshly, but you shall fear your God. . . .

Deuteronomy 15:12-15
If a fellow Hebrew, a man or a woman, sells himself to you and serves you six years, in the seventh year you must set him free. . . .

Jeremiah 34:14-17
Every seventh year, each of you must free his Hebrew brother who has sold himself to you. He may serve you six years, but then you must let him go free. But your fathers did not listen or incline their ear. . . .

Ephesians 6:9
And masters, do the same for your slaves. Give up your use of threats, because you know that He who is both their Master and yours is in heaven, and there is no favoritism with Him.

Colossians 4:1
Masters, supply your slaves with what is right and fair, since you know that you also have a Master in heaven.