Exploitation is sin

King David just expressed his desire casually to some friends that it would be great to drink water from Bethlehem from a particular well. Three valiant soldiers, risked their lives, broke the Philistine stronghold and brought that water. “But David would not drink it. He poured it out to the Lord and said, “Far be it from me before my God that I should do this. Shall I drink the lifeblood of these men? For at the risk of their lives they brought it.” (I Chronicles 11:18-19)
Free service by divine order: There are people who take free service from others. Certain castes were ascribed a lower status, ought to serve other castes. This was free service as it was done to pay for the sins of the past. Only yearly grains and some dresses were provided. That also cannot be demanded. There was no increment or bonus or leave or medical leave.
Oppressed to serve by political order: Certain powerful nations could attack and conquer other nations. The defeated nations become slaves for the conquerors. The victors would oppress the defeated ones and extract all kinds of hard labour. Though the children of Israel were not conquered, they were oppressed by Egypt to build their pyramids and other magnificent structures.
Exploit by economic order: The rich and elite take advantage that they would control resources and give the poor as minimum as possible. The highest paid may get one hundred times what the least is paid.
Social oppression: In many cultures the women are systematically oppressed. It is because of faulty definition of roles in morbid cultures. For example, women were expected to fetch drinking water from a faraway place carrying in pots on their heads or hips. Men will not extend a hand of help.
Family oppression: In some families, even family members are oppressed. The disabled person could be oppressed. A widow in the family would be reduced to a status of a slave or servant. Sometimes grandparents are made servants to serve grandkids.
Am I grateful to others or oppress them?