All just order in the world is based on this: that man give man what is his due. On the other hand, everything unjust implies that what belongs to a man is withheld or taken away from him - and, once more, not by misfortune, failure of crops, fire or earthquake, but by man.
— Josef Pieper, The Four Cardinal Virtues
And if anyone would reduce it to the proper form of a definition, he might say that “justice is a habit whereby a man renders to each one his due by a constant and perpetual will”: and this is about the same definition as that given by the Philosopher (Ethic. v, 5) who says that “justice is a habit whereby a man is said to be capable of doing just actions in accordance with his choice.”
— St. Thomas Aquinas, S.T., II II Q. 58
Justice is the moral virtue that consists in the constant and firm will to give their due to God and neighbor. Justice toward God is called the “virtue of religion.” Justice toward men disposes one to respect the rights of each and to establish in human relationships the harmony that promotes equity with regard to persons and to the common good.
— Catechism of the Catholic Church, #1807
I was asked recently about God’s justice and mercy and specifically, how to reconcile the two. The question caught me off-guard, so I asked for a bit of time to think before giving an answer.
If justice lies in giving someone what they deserve, then mercy is giving someone something that they don’t deserve. God is infinitely just, yes. This ought to catch our attention like nothing else, for what would that mean for most of us, if we’re being completely honest with ourselves? In the face of something so awesome, despair and existential paralysis are the only reasonable responses. Who among us could be saved?
But He is also infinitely merciful, and we can - and should - draw comfort from this. This doesn’t mean we algebraically balance both sides of the equation and then go about our lives. Balancing the two isn’t a puzzle for us to be solved: with man this is impossible, but with God all things are possible.
Or in Catholic-speak: this is a mystery. Let it go.
If we want to try to wrap our minds around it, we have no better example than the parable of the prodigal son. A wastrel son asks for his inheritance early, a request tantamount to announcing to his father “I really would rather not wait until you’re dead,” and takes his leave of his family and home to go out into the world. Finding himself destitute and alone in the midst of famine, he comes to his senses - returning to right reason - and makes his way home. The father would have been completely justified in sending him away again. Who would have blamed him for it? Sorry you spent everything, but we’re done here. Go figure it out elsewhere. Instead, incredibly, the exact opposite happens: he is welcomed home and restored to his place. He desires our restoration and reconciliation. He will run to meet us on the road like the father in the parable.
Neither can truly exist without the other. Mercy without justice is the mother of dissolution, says the Angelic Doctor. Justice without mercy, he continues, is cruelty. These two find their nexus in the person of Christ, Emmanuel, who made his dwelling among us and told us to be merciful as our Father is merciful.