Aristotle defined justice as treating equals equally and unequals unequally. On his definition, God is unjust, for he treats unequals equally. And he expects us to do the same. 

Consider Jesus’ words: “You have heard that it was said, ‘Love your neighbor and hate your enemy.’ But I tell you: Love your enemies and pray for those who persecute you, that you may be sons of your Father in heaven. He causes his sun to rise on the evil and the good, and sends rain on the righteous and the unrighteous. If you love those who love you, what reward will you get? Are not even the tax collectors doing that? And if you greet only your brothers, what are you doing more than others? Do not even pagans do that? Be perfect, therefore, as your heavenly Father is perfect” (Matt. 5.43–48). 

Tomorrow I will write about how to love your enemies, but today I want to write about why we ought to love them. 

First, he articulates the principle of justice as it was understood in his day: “Love your neighbor and hate your enemy.” This is simply another way of saying, “Treat equals equally (with love) and unequals unequally (with hatred).” 

Second, he offers his own understanding of “perfection”: “Love your enemies and pray for those who persecute you.” In other words, he commands us to treat our enemies (unequals) as our neighbors (equals). 

Third, he offers several reasons for practicing this perfection: (1) God treats unequals equally: “He causes his sun to rise on the evil and the good, and sends rain on the righteous and the unrighteous.” (2) Treating unequals equally is a family characteristic, so to speak. Those who claim to be God’s children must act like him (“that you may be sons of your Father in heaven”). (3) God’s children practice a righteousness that exceeds not only that of the Pharisees and teachers of the law (5.20) but also that of the tax collectors and pagans. Jesus’ question—“What are you doing more than others?”—is a constant challenge to our moral mediocrity. 

God’s moral excellence, you see, does not consist of mere justice. Paul writes, “at just the right time, when we were still powerless, Christ died for the ungodly. Very rarely will anyone die for a righteous man, though for a good man someone might possibly dare to die. But God demonstrates his own love for us in this: While we were still sinners, Christ died for us” (Rom. 5.6–8). God’s moral excellence consists of grace, which forgives the unjust and empowers them to practice righteousness. Paul, again: “you have been set free from sin and have become slaves to God, the benefit you reap leads to holiness, and the result is eternal life” (Rom. 6.22). 

In eternity, there will be absolute justice. What else are heaven and hell for? But for now, God practices grace—a seeming “injustice” that is actually good news for everyone.