You shall not have in your pouch alternate weights, larger and smaller. You shall not have in your house alternate measures, a larger and a smaller. You must have completely honest weights and completely honest measures if you are to endure long on the soil that the LORD your God is giving you. For everyone who does those things, everyone who deals dishonestly, is abhorrent to the LORD your God. (Deut 25:13-16)In business and commerce, it used to be a problem for people to have two different measures: a big one for friends, a little one for other people. So if you bought a measure of grain, not everybody got good treatment. Somebody got shortchanged.
Jesus made sure we understood that this applies to our social dealings with people too. In Luke 6, we see Jesus' teaching on loving our enemies as part of the same conversation as not having a double-standard. "If you love only those who love you ... if you do good only to those who do good to you ... even sinners do that. Be merciful ... Do not judge or condemn ... Forgive ... For with the measure you use it will be measured to you." It's all of the same train of thought; it forms a cohesive whole.
I think the most prevalent area in which I see double-standards is when people talk politics. Time after time, each group points out the other group's wing-nuts and claims they are representative; each group looks at its own wing-nuts and claims they are by no means representative. Each group points fingers at the others; each group quietly gives its own a free pass. Transgressions of the other group must be discussed today; our own group's problems ... well, maybe we'll get around to that someday. If someone in the other group does something wrong, their group identity must be pointed out and made partially to blame. If someone in our own group does something wrong, the group identity is not mentioned; it's clearly irrelevant. No matter what the other group is doing, the meanest and lowest motivations are assumed. No matter what a person's own group is doing, the best and highest motivations are assumed. And the odd thing is, a certain percentage of people could probably manage to read this paragraph and suppose that kind of thing mainly happens on the other side of the fence.
I can't help but wonder: What would happen if we didn't have a false measure, a dishonest scale, a double standard? What would happen if the problems of our ideological enemies were treated as kindly and charitably as our own? What would happen if we treated our enemies with the same benefit of the doubt and willingness to forgive that we reserve for our own side? If we treated others as we would want to be treated, would we still have true enemies?