Rom 10:16-18, Rom 1:18-20, Ps 50:6, Ps 97:6
The Old Testament says that all things reveal the glory of God. (Psalm 19:1-4, Psalm 50:6, Psalm 97:6)
Psalm 19:1 The heavens declare the glory of God; and the firmament sheweth his handywork. 2 Day unto day uttereth speech, and night unto night sheweth knowledge. 3 There is no speech nor language, where their voice is not heard. 4 Their line is gone out through all the earth, and their words to the end of the world. In them hath he set a tabernacle for the sun,
Psalm 50:6 And the heavens shall declare his righteousness: for God is judge himself. Selah.
Psalm 97:6 The heavens declare his righteousness, and all the people see his glory.
Since God has revealed Christ through all things, there will be no excuse for people not to hear of Christ. (Romans 10:16-18, Romans 1:18-20)
Romans 10:16 But they have not all obeyed the gospel. For Esaias saith, Lord, who hath believed our report? 17 So then faith cometh by hearing, and hearing by the word of God. 18 But I say, Have they not heard? Yes verily, their sound went into all the earth, and their words unto the ends of the world.
Romans 1:18 For the wrath of God is revealed from heaven against all ungodliness and unrighteousness of men, who hold the truth in unrighteousness; 19 Because that which may be known of God is manifest in them; for God hath shewed it unto them. 20 For the invisible things of him from the creation of the world are clearly seen, being understood by the things that are made, even his eternal power and Godhead; so that they are without excuse: