The Scriptures teach natural and supernatural revelation. Rom 1:19-20 shows natural revelation:
19 because that which is known about God is evident m]">[
m]within them; for God made it evident to them. 20 For since the creation of the world His invisible attributes, His eternal power and divine nature, have been clearly seen, being understood through what has been made, so that they are without excuse.
But natural revelation does not reveal the way of salvation
1For that you need the Scriptures as in Psalm 19:
The law of the Lord is perfect, restoring the soul;
The testimony of the Lord is sure, making wise the simple.
This is synthesized by the first chapter of the Westminster Confession of Faith:
1. Although the light of nature, and the works of creation and providence do so far manifest the goodness, wisdom, and power of God, as to leave men inexcusable; (
Rom. 2:14–15,
Rom. 1:19–20,
Ps. 19:1–3,
Rom. 1:32,
Rom. 2:1) yet they are not sufficient to give that knowledge of God, and of his will, which is necessary unto salvation. (
1 Cor. 1:21,
1 Cor. 2:13–14) Therefore it pleased the Lord, at sundry times, and in divers manner, to reveal Himself, and to declare that His will unto His Church; (
Heb. 1:1) and afterwards, for the better preserving and propagating of the truth, and for the more sure establishment and comfort of the Church against the corruption of the flesh, and the malice of Satan and of the world, to commit the same wholly unto writing: (
Prov. 22:19–21,
Luke 1:3–4,
Rom. 15:4,
Matt. 4:4,
7,
10,
Isa. 8:19–20) which maketh the Holy Scripture to be most necessary; (
2 Tim. 3:15,
2 Pet. 1:19) those former ways of God’s revealing His will unto His people being now ceased. (
Heb. 1:1–2)
Make sure to look up the Heb 1 passage. Jesus has revealed all that needs to be revealed in the Scriptures