Imagine a pope convening an ecumenical council and never showing up. Imagine a world leader overruling him as to where it should be held. Imagine only 30 bishops turning up to inaugurate it. Imagine the council then dragging on for nearly two decades.

Imagine no further, for such a council took shape exactly 480 years ago. Its name was the Council of Trent (1545-1563). Recognized as the 19th council in the history of the Catholic Church, it was one of the most impressive and influential councils in Church history. The Catechism of the Catholic Church footnotes its teaching no less than 141 times.

We don’t often hear the word “Tridentine” today except in reference to the form of the Roman Rite formerly called the “extraordinary form.” This is terribly unfortunate because the word “Tridentine” means much, much more. If you are Catholic, most everything you believe was summarized, defined, clarified or dogmatically reexpressed at the Council of Trent. Like it or not, you are “Tridentine” to the core, regardless of which form of the Roman Rite you attend.

The councils that have had the most formative impact on what you believe took place in Nicaea in A.D. 325 and Constantinople in A.D. 381. These two gave rise to the Nicene-Constantinopolitan Creed, which you profess every Sunday. The Council of Trent vigorously reaffirmed this creed, even though Pope Pius IV promulgated another in the wake of the council that serves to elaborate on a correct understanding of the Nicene-Constantinopolitan Creed.

So, if the Council of Trent didn’t change what we believe, what did it do?

It profoundly advanced our understanding of what we believe in ways that can immensely help our spiritual and moral lives today. Whereas the Second Vatican Council is often referred to as a “pastoral council,” Trent is described as a “doctrinal council.” This is an oversimplification, but it does emphasize that the Council of Trent had to respond to critical doctrinal issues that had been challenged during the Reformation.

The doctrine of justification was the central issue, and it has continued to play a major role in ecumenical discussions through the centuries. The “Joint Declaration on the Doctrine of Justification” between the Lutheran World Federation and the Catholic Church in 1997 marks a major milestone in those discussions.

The issue of justification arises from differing interpretations of scriptural passages such as Romans 3:28, where Paul writes that “we consider that a person is justified by faith apart from the works of the law.” This and other passages (e.g., Romans 4:5 and Ephesians 2:8-9) gave rise to Reformed interpretations broadly characterized as “justification by faith alone” (sola fide).

The Council of Trent indeed affirms that we cannot be justified before God without the grace of Jesus Christ. Yet this does not mean that our cooperation is unnecessary for justification, since our free will, moved by God, disposes and prepares us to obtain the grace of justification, and indeed we remain free to accept or refuse that divine grace. To say that we, as sinners, are justified by faith does not mean that nothing else is required of us. In fact, the justice we freely received from God can be preserved and increased through our performance of good works, which are not merely a “fruit” or “sign” of divine justification already received.

On the surface, these distinctions may seem nothing more than theological subtlety. But upon closer examination, our moral and spiritual lives are inevitably shaped precisely by these questions. Do I believe freely? Do I sin freely? Are my good works worth anything in God’s sight? Can I merit God’s grace by performing good works?

If you struggle with these questions, take heart in knowing that the Church’s most zealous and educated apostle, Paul of Tarsus, struggled with them, too.

Before his conversion, St. Paul was convinced that one could be justified by the works of the Law. But his experience of a personal relationship with Jesus Christ convinced him that we are “not justified by works of the law but through faith in Jesus Christ,” for “we have believed in Christ Jesus in order to be justified by faith in Christ and not by works of the law, because by works of the law no one will be justified” (Galatians 2:15-16).

Yet this did not mean for Paul — and neither does it mean for us — that we can do whatever we want and expect it to have no bearing on how we will be judged. In the words of Pope Benedict XVI, “Christian freedom is not libertinism.” More specifically, “The liberation of which St. Paul spoke is not liberation from good works.”

According to Trent, we are saved by faith, provided that we understand genuine faith as faith “in charity” or faith “in love.” The concept of “faith” developed at the Council of Trent and elaborated in the Joint Declaration is a complete entrusting of oneself to Christ, a uniting to Christ, a conformation to Christ and his very life. Paul makes this clear in Galatians 5:14, where he writes that “the whole law is fulfilled in one statement, namely, ‘You shall love your neighbor as yourself.’”

The lengthy and laborious sessions at Trent treated a host of other questions regarding the sacraments, the veneration of saints, purgatory, and papal authority, but it is fair to say that the lens through which all these topics were viewed was the correct understanding of faith and justification explained above. If we understand what a genuine relationship with Jesus Christ is, we will understand the way we are nourished for it (i.e., the sacraments), how we are helped in it (i.e., the saints), why we need to be purified to fulfill it (i.e., purgatory), and how we come to know it (i.e., papal authority).

Bishop Robert Barron insightfully remarks that Trent explains better than any psychology or philosophy book what’s wrong with us. Sin, Trent teaches, has “disintegrated” us in such a way that we cannot reintegrate ourselves except through Jesus Christ.

This reintegration depends on faith, and only faith, if we understand faith to be inextricably connected to its complementary virtues of hope and charity. Those three virtues — especially the third — articulate what it means to have a deep, personal relationship with Jesus Christ, as Pope Benedict said, for “charity is the fulfillment of communion with Christ,” and “we are just by being in communion with him and in no other way.”

This anniversary year of the Council of Trent providentially coincides with the Jubilee of Hope. It is a wonderful opportunity to examine our souls in light of how we view faith and works in our lives. Do we believe we are fully justified? How?

What we believe, how we act upon it, and what we expect from it were all treated half a millennium ago in a little town closer to Innsbruck than Rome. No matter which form of the liturgy you attend, your identity as a Catholic is heavily informed by the Council of Trent. If you are in search of something to bolster your hope in this Jubilee Year, look no further than its magnificent teaching.

Daniel B. Gallagher is a lecturer in philosophy and literature at Ralston College. He worked for a decade at the Vatican’s Secretariat of State under Popes Benedict XVI and Francis.