When God speaks directly to people, we call it special revelation. God also speaks to everyone indirectly through natural revelation (also known as general revelation because it is given to all). This happens through the natural world God created. For example, Psalm 19 says that knowledge of God in creation is available to everyone everywhere (see Psalm 19:1–4).
Sadly, not everyone responds positively to God. Paul explains in Romans 1–3 that because of Adam's sin, all people turn away from the knowledge of God found in creation. Without God's grace, natural revelation only condemns people. As Paul says in 1:20, people "are without excuse.”
God can use creation to help people realize he is the one true God. When God's grace supports and empowers this natural revelation, the world's beauty and complexity can inspire a search for the Creator. Paul appealed to natural revelation when he was in Athens as a way to introduce the good news about Jesus (Acts 17:16–31). God's revelation in the natural world and in human nature can encourage people to search for him. And then, through the special revelation God has ultimately given in his Son, Jesus Christ, people can truly know him and experience salvation.
Passages for Further Study