We can prepare. We can strategize, set goals, and know the "why" of our mission. We can gather information about our three-headed enemy: sin, death, and Satan. We can rehearse what we will say when called upon to testify to our faith. Experience can teach us how to be afflicted for Christ's sake.
But when we've got boots on the ground, all our preparation is for nothing if the Holy Spirit doesn't act.
Whatever lessons our experiences teach us, our best efforts aren't the sacrifice God needs or requires from us. God doesn't need more of our time, energy, and attention; our neighbor does. For their sake, God gives us gifts such as time so that we can turn from plotting how we'll best serve God to how we can best serve our neighbor.
But, again, this change in focus is only possible if the Holy Spirit acts.
We're so obsessed with sussing out the significance of our life that we look for meaning in everything. For example, Jesus says, “Greater love has no man than this, that he lay down his life for his friends” (John 15:13). Jesus was referring to himself, not to us. But we apply this verse to anyone who sacrifices their life for us. Jesus points to himself, yet we read it as, "Now you, if you're going to love your friends, lay down your life." Rather than fathom the heavy meaning of Jesus' words and how they point to his torture and execution for the sin of the world, we put the weight of this verse on ourselves. We convince ourselves that he's telling us, "If you want God's favor, if you want to be remembered as a hero or aspiration to others, then sacrifice your life in some remarkable way."
In short, we hear Jesus say, "Whatever your life-goals, they had better be meaningful because God loves a hero. So just watch me and follow my example."
Then the Holy Spirit comes to us, with a preacher in hand, ready to unleash a sermon like Louis Armstrong blasting out "When The Saints Go Marching In" on his trumpet. First, the law sounds a note that reveals our lives are insignificant and meaningless because we're damnable sinners. Then the grace note sounds: Jesus has redeemed us from the condemnation of the law through his suffering, death, and resurrection.
The Holy Spirit calls the tune. Our hearts are liberated from our bondage to creating meaning for our lives. We sing a new song that goes something like this:
“I believe that I cannot by my own reason or strength believe in Jesus Christ, my Lord, or come to Him; but the Holy Spirit has called me by the Gospel, enlightened me with His gifts, sanctified and kept me in the true faith. In the same way, He calls, gathers, enlightens, and sanctifies the whole Christian church on earth, and keeps it with Jesus Christ in the one true faith. In this Christian church, He daily and richly forgives all my sins and the sins of all believers. On the Last Day, He will raise me and all the dead, and give eternal life to me and all believers in Christ,” (Martin Luther, Small Catechism, Explanation of the Third Article of the Creed).
Whatever lessons our experiences teach us, our best efforts aren't the sacrifice God needs or requires from us. At Golgotha, Jesus did everything necessary for our salvation already. The significance and meaning of our lives is that Jesus is our Life. In him, we live, and move, and have our being. His Spirit converts us and translates us into God's kingdom. He has already plotted out our life and life eternal. He calls us, justifies us, and sanctifies us. He daily and richly forgives all of our sin. He will raise us from the dead and give us eternal life.
Christ Jesus and his Spirit have defeated our three-headed enemy. He has overcome our sin-enslaved hearts so that we enjoy all Jesus' works and all the Spirit’s gifts of salvation that are given to us through faith, today and always.