Your husband, your wife, your parents, your children, your employer and your employees all belong to God. Jesus said, “whatever you’ve done to one of these, you’ve done it to me.” This is the ‘why’ of doing what we do as Christians relating to one another.
And the way God calls us to treat each other is Against the Flow of culture as it has always been. The culture of the first century was ungodly in the majority and the culture of today continues to be ungodly. The culture around us is not going to teach us how God wants us to relate to one another. We have to learn this from God Himself.