Thy will be done on earth as it is in heaven
I am encouraged by two seemingly paradoxical truths in this verse. The first is the wonderful knowledge that my Father's will will be done. Unlike the evil Emperor from Star Wars, all things actually do work out according to His plan. As Joseph explained to his brothers, “you meant it for evil against me, but God meant it for good.” God's good plan always happens, so we need not be fearful.
The other encouragement I find from His will being done is His will is something I can do. It's not beyond my skill level, or my intelligence, or my spirituality.
Later in the prayer Jesus tells us to forgive, just as we expect the Father to forgive us. This may be something I may not want to do, but it's something I can do, for it is the Father's will that I do it.
(Unfortunately, I can choose not to do His will. I have demonstrated over and over again in my life. When Joseph's brothers abused him, they were not acting in a manner expressive of God's will.)
So then the prayer becomes our petition to the Father: "We am asking you, Father, that Your will be done in our lives just as your will is done in heaven."