Why did Jesus have to be perfect?

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My daughter Zoe always corrects me. Whenever I tell her nobody’s perfect, she always responds except Jesus!  I think I’m on safe ground saying that most Christians share the belief that Jesus is perfect. I think I’m also safe saying that fewer can explain why.

To find the answer, we need to go back to the beginning. Sin can be traced back to the Garden of Eden where man rejected the order God had established and attempted to replace it with one where man would be equal to God:

“God knows well that when you eat of it your eyes will be opened and you will be like gods, who know good and evil.” — GENESIS 3:5

By rejecting God’s order, man forfeited eternal life and became heir to death:

“The LORD God gave the man this order: You are free to eat from any of the trees of the garden except the tree of knowledge of good and evil. From that tree you shall not eat; when you eat from it you shall die.”—GENESIS 2:16-17

“By the sweat of your brow you shall eat bread, until you return to the ground, from which you were taken; for you are dust, and to dust you shall return.”—GENESIS 3:19

Moreover, by rebelling against God, man lost the sinless nature which made him acceptable to God and able to be in his presence.


God instituted animal sacrifice, in part, to demonstrate his perfect justice—sin requires payment. Some argue that God should just forgive man of his trespass and absolve his debt. Doing so, however, would not be just. It would place sinners and those who have not sinned as equals before God. It would be an affront to God’s perfect justice. St. Anselm, an 11th century Benedictine monk, Archbishop and Doctor of the Church explains that:

“It is, therefore, not proper for God thus to pass over sin unpunished… if sin be passed by unpunished…there will be no difference between the guilty and the not guilty; and this is unbecoming to God.” —St Anselm of Canterbury, Cur Deus Homo, Book I, Chapter XII

In addition, God’s perfect justice demands a restitution equivalent to what was lost. Ultimately, an animal is not equal to man who was made in the image and likeness of God. An animal could never take man’s place. But neither could the death of a mere man—who is sinful and imperfect—adequately pay back the holiness and perfection Adam had that was lost in Eden:

“But sinful man cannot at all accomplish this justification, because a sinner cannot justify a sinner.”—Cur Deus Homo, Book I, Chapter XXIII

If such a man were sacrificed, his death could only reckon towards his own sins.

“No man, not even the holiest, was ever able to take on himself the sins of all men and offer himself as a sacrifice for all.” —Catechism of the Catholic Church #616

The only acceptable sacrificial victim would be one who shared man’s human nature and was able to truly die and suffer the penalty for sin which is death. But who, unlike man in his fallen state, was sinless. This way his death would not be payment for his own sins, but could be offered for all.


The debt owed to God is infinite because his authority, which was rebelled against, and his glory, which was dishonored, are infinite. This payment is too great for man to payback. Although no one but man owed the debt, no one but God was capable of paying it to satisfy divine justice. Only a victim having both natures could be a perfect sacrifice. St. Anselm describes this redeemer as the God-man:

“For God will not do it, because he has no debt to pay; and man will not do it, because he cannot. Therefore, in order that the God-man may perform this, it is necessary that the same being should be perfect God and perfect man, in order to make this atonement.” —St Anselm of Canterbury, Cur Deus Homo, Chapter VII


Through the incarnation, God incorporated human nature into himself so that a perfect man might make a perfect sacrifice thereby satisfying God’s perfect justice and restore to the human race what was lost in the Garden of Eden. When Jesus rose from the dead and ascended to heaven, he did so with our human nature, which now sits at the right hand of the Father. He took on our human nature so we could partake of his divine nature:

“For the Son of God became man so that we might become God.” “The only-begotten Son of God, wanting to make us sharers in his divinity, assumed our nature, so that he, made man, might make men gods.”Catechism of the Catholic Church #460

So, despite being seven years old, Zoe is right, Jesus is perfect. My next step as Dad is to help her understand why. P.S. Zoe is the little girl holding the cards just below this sentence!


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Dan Gonzalez is both author and designer of the MassExplained blog and MassExplained iPad app. Through fun games and colorful flash cards, Dan's new app, Catholic Word & Games, teaches Catholic vocabulary to children. His design work can be seen at Visit to browse his Catholic t-shirt line. Dan's reversion story can be read here.

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