Catechism of the Catholic Church

618 The cross is the unique sacrifice of Christ, the "one mediator between God and men". ⁴⁵² But because in his incarnate divine person he has in some way united himself to every man, "the possibility of being made partners, in a way known to God, in the paschal mystery" is offered to all men. ⁴⁵³ He calls his disciples to "take up [their] cross and follow [him]", ⁴⁵⁴ for "Christ also suffered for [us], leaving [us] an example so that [we] should follow in his steps." ⁴⁵⁵ In fact Jesus desires to associate with his redeeming sacrifice those who were to be its first beneficiaries. ⁴⁵⁶ This is achieved supremely in the case of his mother, who was associated more intimately than any other person in the mystery of his redemptive suffering. ⁴⁵⁷

Apart from the cross there is no other ladder by which we may get to heaven. ⁴⁵⁸

619 "Christ died for our sins in accordance with the scriptures" (I Cor 15:3).

620 Our salvation flows from God's initiative of love for us, because "he loved us and sent his Son to be the expiation for our sins" (I Jn 4:10). "God was in Christ reconciling the world to himself" (2 Cor 5:19).

621 Jesus freely offered himself for our salvation. Beforehand, during the Last Supper, he both symbolized this offering and made it really present: "This is my body which is given for you" (Lk 22:19).

622 The redemption won by Christ consists in this, that he came "to give his life as a ransom for many" (Mt 20:28), that is, he "loved [his own] to the end" (Jn 13:1), so that they might be "ransomed from the futile ways inherited from [their] fathers" (I Pt 1:18).

623 By his loving obedience to the Father, "unto death, even death on a cross" (Phil 2:8), Jesus fulfils the atoning mission (cf. Is 53:10) of the suffering Servant, who will "make many righteous; and he shall bear their iniquities" (Is 53:11; cf. Rom 5:19).