In Christian circles, it’s often expressed that hell represents an outdated Old Testament doctrine, seemingly at odds with Jesus’s powerful message of love. This misunderstanding clearly stems from a flawed comparison between the Old Testament’s depiction of God as one of wrath and judgment and the love and mercy exemplified by Jesus. But the fact is, hell is not an Old Testament doctrine at all. The ancient Hebrew concept of sheol only hints at hell; everyone goes to sheol upon death, regardless of how they lived. It does not function as a place of judgment, or punishment. Hell is indeed a New Testament doctrine; Jesus emphasized the concept of hell because he understood the importance of confronting our human condition before God. He taught that when we try to live without God, we create our own hell. While Jesus never specifically used the word “hell,” his messages were designed to awaken his audience from complacency and self-satisfaction. Jesus wanted to make them aware of the real possibility of hell existing within themselves—in each of us. Like Jesus's preaching, Pope St. John Paul II, in his encyclical Redemptoris missio, used the doctrine of hell to warn human beings that “the Church’s mission derives not only from the Lord’s mandate but also from the profound demands of God’s life within us” (§11). On this point, St. John Paul II warned that those who take their status in Christ for granted and do not respond to God's grace in their lives by bearing witness to it risk damnation (cf. Lumen gentium §14).
The parable of the wedding banquet we hear today shows how Jesus tries to alert his audience to the real possibility of hell if they remain complacent. Matthew’s version adds a denouncement of the guests ejected from the banquet for lacking a wedding robe. In the parable, this person represents all those gathered for the kingdom who failed to undergo the conversion symbolized by the wedding robe. At the judgment, represented by the image of the King’s coming to see the guest, they will be found lacking the “wedding robe” of good works, and therefore, they must be expelled. St. Thomas Aquinas, in his commentary on the Gospel of Matthew, explains that the wedding garment represents Christ Himself. So, the parable is basically about the invitation to put on Christ. We can put on Christ through the sacrament; when we are baptized in Christ, we have put on Christ. We can also put on Christ through charity and love, and let the peace of Christ rejoice in our hearts. St. Thomas also reminded us that we can put on Christ through remembering death and through charitable works.
To wear a wedding garment means to put on Christ through good works, leading a holy life, and demonstrating true charity; lacking any of these indicates troubling news.