The words “children of God” are a metaphor. That is, the “children of God” are the people of God (see: Exodus 4:22-23; Romans 8:14; Galatians 3:26). In the same way a father cares for his children, so God loves and cares for his people. God’s people love, obey, and rely on God in the same way children love, obey, and rely on their father.
Sometimes God’s people are called “children of God,” but sometimes they are called “sons of God. This is because the word “sons” in “sons of God” is talking about both males and females.
Humans are not sons or children of God in the same way that Jesus is the Son of God. Jesus has always been the Son of God, and he will always be the Son of God. Jesus created people. Jesus was not created. He is God. However, people who believe in Jesus are adopted into God’s family. God will give them an inheritance along with Jesus (see: Romans 8:17; Ephesians 1:5).