Can a Catholic lose their salvation?

Yes. Baptism gives real salvation and sanctifying grace, but a Catholic can later reject that grace through mortal sin. God remains ready to forgive anyone who sincerely repents.

Salvation can be rejected. Scripture describes salvation as a gift already received, a life in which Christians must persevere, and a final deliverance still to come. St. Paul warns baptized believers, “Let anyone who thinks that he stands take heed lest he fall” (1 Cor 10:12). Jesus says that the one who endures to the end will be saved (Mt 24:13). These warnings would have little meaning if apostasy and grave sin could never separate a Christian from God.

How grace is lost. Mortal sin destroys charity in the heart and deprives the soul of sanctifying grace (CCC 1861). For a sin to be mortal, three conditions must be present: grave matter, full knowledge, and deliberate consent (CCC 1857-1859). Examples of grave matter include adultery, murder, serious theft, and deliberately missing Sunday Mass without a serious reason. Personal guilt may be reduced when knowledge or freedom is impaired, but grave actions remain objectively serious.

What this does not mean. Every weakness, temptation, or minor fault does not sever friendship with God. Venial sin wounds charity but does not destroy sanctifying grace (CCC 1862-1863). A Catholic should avoid both despair and presumption. Despair denies God’s mercy, while presumption assumes salvation without conversion or perseverance (CCC 2091-2092). No created power can tear a faithful person away from Christ against that person’s will (Rom 8:38-39), but a person can freely turn away.

How a person returns. Christ instituted the Sacrament of Reconciliation for baptized people who fall into serious sin (Jn 20:22-23; CCC 1446). Perfect contrition, arising from love of God above all else, reconciles a person with God when it includes the firm intention to confess as soon as possible (CCC 1452). Ordinarily, a Catholic conscious of mortal sin must receive sacramental absolution before Holy Communion (CCC 1457; Canon 916).

In practice. If you are aware of mortal sin, do not receive Communion until you have gone to confession. Make an act of contrition, arrange confession promptly, and trust Christ’s mercy. He does not abandon the repentant sinner. He seeks, forgives, and restores those who return to Him.