The demands our Lord makes in the Sermon on the Mount are impossible for us to meet—unless he has done a supernatural work inside us. Not only does Jesus Christ demand that his disciples go the second mile, he also demands that there be no trace of resentment inside them when they come up against tyranny and injustice because of their commitment to him: “Blessed are you when people insult you, persecute you and falsely say all kinds of evil against you because of me. Rejoice and be glad” (Matthew 5:11–12). There’s no enthusiasm, no natural human quality, that can withstand the strain that Jesus Christ places upon his workers. The only thing strong enough is a personal relationship with him. This relationship must be put to the test until the disciple has just one purpose remaining: “I am here for God to send me wherever he will.” Everything else in a disciple’s life may get muddied, but this relationship to Jesus Christ must remain perfectly clear.

If I am going to be a disciple of Jesus, I must be made one supernaturally. As long as I’m dead set on being a disciple, I can be sure I am not one. Discipleship isn’t a matter of my determination, but of God’s: “You did not choose me, but I chose you” (John 15:16). This is the way the call to discipleship begins. I can ignore God’s call, but I can neither generate it nor decide how to answer it. When our Lord makes disciples, he doesn’t ask them to do things they’re naturally cut out for. He asks them to do things they’ve been supernaturally cut out for by his grace.

The Sermon on the Mount isn’t some unattainable ideal. It’s a statement of what will actually happen in me when Jesus Christ has changed my disposition and put into me a disposition like his own. Jesus Christ is the only one who can fulfill the Sermon on the Mount.