When a man applies to join the seminary, one of the hoops he jumps through is a psychological assessment. The Church doesn’t want anyone too strange becoming a priest. Which is ironic, because the psychologist I saw was one of the strangest men I’ve ever met.

My appointment was at 2pm, and I rang the doorbell right on the dot, but the psychologist was surprised to see me! He said I was due at 2:30. I later learned that the other seminarians went through the same thing. I think he wanted to know how we’d react to a socially awkward situation.

After I apologised for the “mix up,” I was left in his study while he tidied up in the kitchen. I was left waiting for about ten minutes. Again, I later learned that all the other seminarians went through the same thing. I like to imagine that he had a peephole built into the eyes of an oil painting, so that he could watch what I did while I waited. When he returned, he observed me for a while, and then he said, “You have a young-looking face. Even when you are 60, you’ll look 20 years younger than you are.” What are you supposed to say to something like that??

The psychological assessment took an hour. First there was an ink blot test. Then I was shown photos of people from the 1950s, and asked to indicate if they were ugly, average, or good-looking. Then he read out phrases, and I had to reply with the first thing that came to mind.

Eventually, he declared that I was “boringly normal.” But he did add that I have a volcanic temper. “You don’t lose your temper often,” he said, “but when you do, you blow your stack.” I’d never experienced that before. I didn’t agree with him. But I thanked him, went on my way, and obviously I was accepted into the seminary.

About 2 years later, the psychologist was completely vindicated. Something happened which filled me with white hot rage. I didn’t get violent, but I struggled to sleep at night. I struggled to concentrate during the day. Anger clouded my vision and monopolised my thoughts.

I consulted a priest — as you do. He was excellent. As I told my story, he didn’t interrupt, and he never told me to calm down. I was so angry I swore — which I never did, especially in the company of a priest! But he didn’t flinch.

At the end of my spiel, the first thing he spoke of was “righteous anger.” He invoked today’s Gospel. Jesus “is like us in all things but sin.” And yet in the cleansing of the Temple we see him angry. Violently angry. That demonstrates that anger is not, in itself, sinful. It’s easy to forget that. People often confess anger as though it’s a sin. But it’s not always. Righteous anger is a thing. Sometimes, justice compels us to be angry. Certainly, it compelled our Lord.

When I hear or read today’s Gospel, my mind always goes back to that conversation with a good priest in the midst of my anger. What he said next is also important. Having identified the righteousness of my anger, he also identified wrath: one of the seven deadly sins. And with that, he donned a purple stole, and declared it was time for confession.

I had to pause a moment and examine my conscience. What is the difference between righteous anger, which even Jesus exercised, and wrath, which is a deadly sin? With the Holy Spirit’s help, I discerned the answer, because when we approach the Sacrament of Reconciliation in good faith, the Holy Spirit will always assist us. (Guaranteed!)

Righteous anger is godly; it derives from justice. Wrath is ungodly; it excludes mercy. And there is the crux. In God, we find infinite Justice and infinite Mercy. There’s tension between them, but they’re not opposed. On the contrary: in God, justice and mercy are perfectly united; two sides to the one coin. But in our human frailty, justice and mercy can be opposed. And wrath is just one example of what that opposition looks like.

There’s a reason wrath is called a deadly sin. Its fruits are toxic. In my case, it caused inestimable damage to several relationships. Years later, those relationships are salvaged, but scarred. Nonetheless, despite its lasting damage, I don’t regret that terrible experience. Which brings me to today’s Second Reading — one of my favourites. In his first letter to the Corinthians, St Paul describes Christ crucified as “an obstacle” to the Jewish mind and “madness” to the pagan mind. But to the Christian mind, the crucifixion is “the power and the wisdom of God.”

In his second letter to the same, St Paul elaborates on what he wrote in his first letter: God’s power is made perfect in our weakness; when we are weak, then God is strong.

The wrath which afflicted me — the deadly sin which I committed — diminished me. It hurt people I love, and it cut me off from God’s friendship. But in confession, I was reconciled with God. And the grace that flowed from that helped me to repudiate the spirit of wrath, forgive my friends, and enable them to forgive me. That healing, unlike the absolution it flowed from, wasn’t instantaneous. It happened slowly, painfully, but inexorably.

Many years later, there are still scars, because grave sins always leave scars. They aren’t healed in this life — some things have to wait for the next. But in the meantime these scars we all carry are assets. Paul even suggests we boast of them, because in these God’s power is made perfect.

In my case, that terrible, unforgettable experience gives me insight into other people’s struggles with wrath and unforgiveness. And I have insight into righteous anger too, and how to discern that from wrath. All of which helps me to counsel others as I was once counselled. But most importantly, it keeps me humble. I know that I have to struggle to be like the Lord: slow to anger, rich in mercy.

This is just one example of how weakness — even sinfulness — can strengthen us. Not automatically! It’s never automatic. We have to pray through our weakness. We have to approach Christ, on his cross, and suffer with him. But when we do that, our wounds become fountains of grace. In and through the cross, we’re able to bless the people around us. And we can say with St Paul, “when I am weak, then I am strong.”