The Israelites were instructed to treat women who were from conquered cities with dignity. If they found a woman they wanted for a wife, then they would take them home, have them shave their head, trim their names, change clothes, and then mourn her family for a month. After that, they may take her as a wife. If he is not pleased with her, he should release her, but not sell her or beat her.
Also, if a man prefers one wife over another, he should not prefer her children above others, but should follow inheritance laws indiscriminately. While this is somewhat foreign to us today, it is a principle that speaks to the need to not show favoritism among family members, as it is breeds contempt and resentment.
When believers have an upper hand over another individual, it is important to treat them fairly. If you oppress someone else, then God will be displeased and judgement can come. God takes justice seriously.
Devoted To You 