Upvote:3
Canonization, beatification, etc., do not change one's merit.
Fr. John Hardon, S.J., defines "merit" in his Catholic Dictionary:
Divine reward for the practice of virtue. It is a Catholic doctrine that by his good works a person in the state of grace really acquires a claim to supernatural reward from God. "The reward given for good works is not won by reason of actions which precede grace, but grace, which is unmerited, precedes actions in order that they may be performed meritoriously" (II Council of Orange, Denzinger 388).
Fr. Hardon enumerates what can increase merit:
Factors that increase a person's supernatural reward for good works performed in the state of grace. There are four such factors:
the degree of sanctifying grace in which a person does some morally good action;
the intensity of will with which an act is done;
the sublimity of the action performed; and
the purity of love or selflessness that animates the performance.
Difficulties of themselves do not increase supernatural merit, but, provided that a difficulty is not culpable, it normally demands additional effort of will and thus indirectly adds to the merit derived from a morally good act done in the state of grace.
See St. Thomas Aquinas's Summa Theologica I-II q. 114 ("On Merit") for more detail.
Upvote:5
Canonization does not change an individual's status in the eyes of Godβnothing can change that. What it does is make a declaration about what the Church thinks of them:
By canonizing some of the faithful, i.e., by solemnly proclaiming that they practiced heroic virtue and lived in fidelity to God's grace, the Church recognizes the power of the Spirit of holiness within her and sustains the hope of believers by proposing the saints to them as models and intercessors.
(Catechism of the Catholic Church, paragraph 828)
In other words, what canonization does is make it official to all Catholics that the Church recognizes, by the power of the Holy Spirit that acts in her and guides her, that a certain person has lived an undeniably holy and grace-filled life; that they may be used as models for our attempt to live out a Christian life; and that we here on Earth may ask them to intercede for us with God, to ask for God's mercy and intervention on our behalf.
It is not always the case, however, that those Christians who are recognized as saints were formally canonized. The Blessed Virgin Mary, for example, has always been thought holy, but never gone through a canonization process (not that she would have an issue!) But usually, in relatively modern times, there's been some process that the Church has put candidates for such great holiness through, not for the candidate's benefit but for the Church's.