14 In carefully planning and preparing the salvation of the whole human race the God of infinite love, by a special dispensation, chose for Himself a people to whom He would entrust His promises. First He entered into a covenant with Abraham (see Gen. 15:18) and, through Moses, with the people of Israel (see Ex. 24:8). To this people which He had acquired for Himself, He so manifested Himself through words and deeds as the one true and living God that Israel came to know by experience the ways of God with men. Then too, when God Himself spoke to them through the mouth of the prophets, Israel daily gained a deeper and clearer understanding of His ways and made them more widely known among the nations (see Ps. 21:29; 95:1-3; Is. 2:1-5; Jer. 3:17). The plan of salvation foretold by the sacred authors, recounted and explained by them, is found as the true word of God in the books of the Old Testament: these books, therefore, written under divine inspiration, remain permanently valuable. "For all that was written for our instruction, so that by steadfastness and the encouragement of the Scriptures we might have hope" (Rom. 15:4).
Source: Dei Verbum (Vatican.va)