12 "It is 'God, who is rich in mercy' whom Jesus Christ has revealed to us as Father: it is his very Son who, in himself, has manifested him and made him known to us." I wrote this at the beginning of my Encyclical Dives in Misericordia , to show that Christ is the revelation and incarnation of the Father's mercy. Salvation consists in believing and accepting the mystery of the Father and of his love, made manifest and freely given in Jesus through the Spirit. In this way the kingdom of God comes to be fulfilled: the kingdom prepared for in the Old Testament, brought about by Christ and in Christ, and proclaimed to all peoples by the Church, which works and prays for its perfect and definitive realization. The Old Testament attests that God chose and formed a people for himself, in order to reveal and carry out his loving plan. But at the same time God is the Creator and Father of all people; he cares and provides for them, extending his blessing to all (cf. Gn 12:3); he has established a covenant with all of them (cf. Gn 9:1-17). Israel experiences a personal and saving God (cf. Dt 4:37; 7:6-8; Is 43:1-7) and becomes his witness and interpreter among the nations. In the course of her history, Israel comes to realize that her election has a universal meaning (cf. for example Is 2:2-5; 25:6-8; 60:1-6; Jer 3:17; 16:19).
Source: Redemptoris Missio (Vatican.va)