You can't do it

To love one’s enemy is not something that can possibly emerge naturally from a person; it comes as a super-added gift of grace. But because Bonhoeffer has already grounded the capacity for obedience in Jesus Christ rather than in the disciple’s human capacities, obedience is made possible despite its impossibility for human nature. Obedience requires Christ precisely because Christ’s commands transcend human ability.—Bonhoeffer the Assassin?, page 155