Catechism of the Catholic Church

218 In the course of its history, Israel was able to discover that God had only one reason to reveal himself to them, a single motive for choosing them from among all peoples as his special possession: his sheer gratuitous love. ³⁸ And thanks to the prophets Israel understood that it was again out of love that God never stopped saving them and pardoning their unfaithfulness and sins. ³⁹

219 God's love for Israel is compared to a father's love for his son. His love for his people is stronger than a mother's for her children. God loves his people more than a bridegroom his beloved; his love will be victorious over even the worst infidelities and will extend to his most precious gift: "God so loved the world that he gave his only Son." ⁴⁰

220 God's love is "everlasting": ⁴¹ "For the mountains may depart and the hills be removed, but my steadfast love shall not depart from you." ⁴² Through Jeremiah, God declares to his people, "I have loved you with an everlasting love; therefore I have continued my faithfulness to you." ⁴³

221 But St. John goes even further when he affirms that "God is love": ⁴⁴ God's very being is love. By sending his only Son and the Spirit of Love in the fullness of time, God has revealed his innermost secret: ⁴⁵ God himself is an eternal exchange of love, Father, Son and Holy Spirit, and he has destined us to share in that exchange.