It is rare that the gift of theological genius joins to a heart alive with the love of Christ and a will singularly committed to fulfilling God’s will for the sake of the Kingdom. When it does, theology, the Catholic Church and the world are changed forever.

Germain Gabriel Grisez was one of these rare souls. He died at home Feb. 1. He was 88 years old. To the end, he was researching and writing, although health concerns occupied more of his time than he preferred. He was still Skyping with colleagues and students. He was still holding round-table conferences with collaborators.

Few are aware of the debt that the Catholic Church owes to Germain Grisez. As a young scholar, in collaboration with the great Jesuit moral theologian John Cuthbert Ford, he was instrumental in formulating the idea that constituted the central theoretical construct of the papal encyclical Humanae Vitae, i.e., of the unbreakable connection between the unitive and procreative meanings of the marital act.

He was the first Catholic scholar in the postwar period to have the foresight, courage and smarts to dedicate an entire book to the defense of the integrity of the marital act (Contraception and the Natural Law, 1964), which was why Pope Paul VI consulted him on the drafting of his encyclical.

Grisez published a powerful defense of the sanctity of human life three years before Roe v. Wade (Abortion: the Myths, the Realities and the Arguments, 1970). And before assisted suicide was on anyone’s radar, he published a great work with his friend and former student Joseph Boyle (Life and Death With Liberty and Justice: A Contribution to the Euthanasia Debate, 1979).

He was always ahead of the curve on issues in moral theology.

In his collaborative work with John Finnis and Joseph Boyle, Grisez intellectually demolished the pseudo-Catholic moral methodology regnant at the time known as “Proportionalism,” while luminously defending the integrity of moral absolutes. Because of this, John Paul II brought him to Rome prior to the drafting of Veritatis Splendor for a one-on-one consultation on matters pertaining to the crisis in moral theology. And anyone familiar with that august encyclical will see Grisez’s clear fingerprints in the Pope’s multiple references to the way that God designed moral truths to protect the “goods” of the human person.

Those who don’t know his work well would likely say that his most important scholarly contribution was the concept of “basic human goods.” I don’t think Grisez would have said this. His overarching interest and heartfelt preoccupation in moral theology was to advance the idea of the beatifying communion of all persons, human, angelic and divine, in the Kingdom of God as the ultimate end of human existence.

During the pontificates of St. John Paul II and Benedict XVI, he repeatedly said we need an encyclical on the Kingdom of God, for people no longer believe in heaven and hell or see that these are precisely what’s at stake in human choosing, but think vaguely that everybody will end happy (everybody, perhaps, except Hitler) as long as they’re sincere.

He told every bishop he met during these years to write a pastoral letter on heaven. To date, neither an encyclical nor a pastoral letter on heaven has been written, at least not to my knowledge.

Grisez’s body had been giving him troubles for some time. Medical interventions had held his prostate cancer at bay for over a year, but a scan last week showed that it had badly invaded his bones. To be ready to deal with the problems of his final months, he began hospice last Monday.

On Tuesday, he wrote me saying, “My life expectancy is now six months or less, and I have a hospice care program, which will provide a lot of help while I remain in my place [at my son’s house].” He said, “When you have time and feel up to it, we might spend an hour trading data about each other’s health.”

I did not see the message until the next day, Jan. 31. When I did, I emailed him at once, “Can you Skype today?” He wrote back, “I will try it right now.” Then nothing. After a few minutes, I tried Skyping him. No answer. I tried again. Nothing. Later, I called his cellphone. It went to voicemail. After dinner, I called his son and daughter-in-law, in whose home he lived, and spoke with the latter. I told her I had been trying to reach him all day, but was having trouble: “Is anything wrong?” “Well, yes,” she said. “Morphine was administered for pain today; he fell asleep; and I can’t wake him.” He was alive, she said, and could be stirred to moments of blurry consciousness, but not to lucidity. I told her I’d call in the morning. That night I sent him an email telling him I was very concerned, that my family and I were praying for him, and that I loved him.

He never opened the email. He died around 7:15am, never regaining lucidity. His body just gave out.

In the last eight months he said to me six or so times that he wanted to finish God’s work and then go home. Recently, as his cancer worsened and his prospects for life were narrowing, I asked him if his faith in the Kingdom was ever assailed. He said “No, of the Kingdom, I have no doubts.”

Heroes are few today — and less so anywhere than among moral theologians. Whether he was a saint is for Jesus to determine. But I can say with certitude that Germain Grisez was a hero of Catholic moral theology.

The Church has lost a hero; a truly great theologian; a man with a holy fear of God, but unafraid of men; a man who loved neither money, nor praise, nor reputation; a man whose theological acumen towered over most of his age; a man who submitted his enormously gifted intelligence entirely to the service of Jesus and his Church. He was an intellectual father to many and a trusted friend to those fortunate enough to get to know him. Germain Grisez will be sorely missed.

An eminent Australian philosopher said recently that he thought Grisez was the greatest theologian since St. Thomas Aquinas. Some may scoff at the comparison. They scoffed at Aquinas right after his death in the 1270s, when the bishops of Paris and Oxford issued condemnations of the great friar’s work.

But wisdom was vindicated by all the friar’s children. And so it will be again with Germain Grisez. Of that, I have no doubts.

Eternal rest grant to Germain Gabriel Grisez, O Lord, and let perpetual light shine upon him.

May he rest in peace.

E. Christian Brugger is a senior fellow of ethics and director of the Fellows Program at the Culture of Life Foundation in Washington, D.C.

He lives in Jacksonville Beach, Florida, with his wife, Melissa.