3 God, who through the Word creates all things (see John 1:3) and keeps them in existence, gives men an enduring witness to Himself in created realities (see Rom. 1:19-20). Planning to make known the way of heavenly salvation, He went further and from the start manifested Himself to our first parents. Then after their fall His promise of redemption aroused in them the hope of being saved (see Gen. 3:15) and from that time on He ceaselessly kept the human race in His care, to give eternal life to those who perseveringly do good in search of salvation (see Rom. 2:6-7). Then, at the time He had appointed He called Abraham in order to make of him a great nation (see Gen. 12:2). Through the patriarchs, and after them through Moses and the prophets, He taught this people to acknowledge Himself the one living and true God, provident father and just judge, and to wait for the Savior promised by Him, and in this manner prepared the way for the Gospel down through the centuries.
Source: Dei Verbum (Vatican.va)