How does someone become a saint (canonization)?

It helps to separate two meanings of the word "saint." In the broad biblical sense, every person fully alive with God in heaven is a saint, named or not — a quiet grandmother, an unknown martyr, a faithful friend. That vast, mostly hidden crowd is the real population of heaven. Canonization is something narrower: it's the Church carefully examining one life and declaring, with confidence, "this person is with God — hold them up as an example and ask their prayers."

The process unfolds in stages, and it's deliberately slow and cautious. It usually begins only after the person has died, when their local bishop opens an investigation into their life, gathering testimony and writings to ask one question: did this person live the Christian virtues to a heroic degree? If the evidence holds, the person is named "Venerable." The Church is essentially doing careful homework, making sure it isn't honouring a reputation that doesn't match reality.

Two further steps usually follow, and this is where miracles come in. "Beatification" — being declared "Blessed" — normally requires a verified miracle attributed to the person's intercession, often a medically unexplainable healing that doctors and theologians scrutinise hard. "Canonization" — being declared a "Saint" — typically requires a second confirmed miracle. The logic is that a genuine miracle is treated as a kind of confirmation from God himself that the person really is with him and really does pray for those who ask. (Martyrs, who gave their lives for the faith, follow a somewhat shorter path.)

Notice what the Church is and isn't claiming. It isn't promoting the person to a higher rank or granting them powers. It's making a public, trustworthy judgment that this man or woman is in heaven and may be honoured everywhere, with a feast day and the freedom to name churches after them. Far more saints exist than will ever be canonized; canonization simply lifts up a few, with care, as proven models and intercessors for the whole Church.

Canonization gives us reliable heroes. Because the Church investigates so rigorously, a canonized saint is someone we can confidently imitate and ask to pray for us, knowing we're not chasing a myth. It also keeps the goal of holiness in front of every kind of person — the saints come from every century, culture, and walk of life, which means there is almost certainly one whose path looks like yours.

• Romans 1:7 — Paul addresses ordinary believers as "saints," showing the word's broad sense of those set apart for God.
• Matthew 5:48 — Jesus' call to "be perfect" sets the universal goal of holiness behind all sainthood.
• 1 Thessalonians 4:3 — "this is the will of God, your sanctification," pointing to holiness as everyone's vocation.
• Revelation 7:9 — a countless multitude before God's throne, an image of how many more saints there are than the Church will ever name.

• CCC 828
• The Second Vatican Council's Lumen Gentium (ch. 5) teaches the universal call to holiness; Pope John Paul II's Divinus Perfectionis Magister (1983) set out the modern procedure for examining and declaring saints.