Therefore, whatever you want others to do for you, do also the same for them, for this is the Law and the Prophets. (Matt. 7:12)
This verse, commonly referred to as the Golden Rule, is found at the very end to the Sermon on the Mount and serves ultimately as a one sentence summary of Jesus' teaching in the sermon on the Law.
find the details about the emperor who had it on the wall in gold for this margin note.
What it does not mean:
While this command is perhaps one of the most commonly cited verses in the Bible, it is regularly misapplied. It is often treated like some form of Christian karma. If I treat people nicely, then people will be nice back. But this is not karma.
This passage says nothing about how others will treat you. The statement concerning the actions of others is aspirational (how you would like others to treat you), not actual (how they will treat you).
In fact, Jesus has already addressed how people will often respond to his disciples. He did so at the beginning of the sermon in chapter 5:
You are blessed when they insult you and persecute you and falsely say every kind of evil against you because of me. Be glad and rejoice, because your reward is great in heaven. For that is how they persecuted the prophets who were before you. (Matt. 5:11)
What it does mean:
Jesus doesn't teach karma here. He's teaching the opposite. Jesus is saying his disciples, citizens of the kingdom, treat others with grace, honor, and respect (the way we would want to be treated), regardless of how others treat them.
The Golden Rule provides a concise summary statement for the overall ethic of the entire Sermon on the Mount. This ethic can be called the kingdom ethic and is testimonial in nature. Jesus calls his disciples to a Testimonial Ethic in the beginning of the Sermon, noting that the good deeds of the kingdom are done so that others might see them and glorify God as a result (Mt. 5:13-16). Developing a kingdom ethic that provides testimony to the power of the gospel to change the human heart, is one aim of Transformational Discipleship.