"In everything do to others as you would have them do to you; for this is the law and the prophets."
The Sermon on the Mount is a wonderful compression of Jesus' teaching. This command is a compression of the Sermon, indeed "all of the law and the prophets." Our God wants to make it easy for us to understand what he wants of us. He, like us, wants to be understood.
It is not difficult to know what is involved in living the Christian life. It may be difficult to live it - in fact Christ tells us this in the very next line - but it is not difficult to know it. Our enemy and his tool the world would have us believe otherwise. He would have us believe it is impossible to know what God wants of us. He would have us believe the Christian life consists primarily in the fulfilling of some dark and mysterious vocation for which we must spend all our efforts fruitlessly searching. Christ never says that. He gives all of us what we need to know to live the Christian life. And it is summed up here in this beautifully concise command to "do unto others as you would have done to you." Perhaps we are scandalized by its simplicity. Perhaps in our pride we want a complicated rule to match how we have complicated our lives. But that wouldn't be refreshing, and Christ promises refreshment.
Say to others what you would have said to you. Be silent for others as you would have them be silent for you. Encourage others because you would be encouraged. Offer a gentle, kind, serene, calm, supportive, encouraging, refreshing, joyous disposition toward others as you would have them do to you. Instruct as you would be instructed. Be for others even if they cannot be for you, because you would have others be for you at times when you know you cannot be for them. Forgive as you want to be forgiven. Completely, unquestionably, repeatedly. Love as you want to be loved. Generously, boundlessly, without a hint that it comes at a price.