A.T. Robertson Commentary Romans 8:14

"For as many as are led by the Spirit of God, these are sons of God." — Romans 8:14 (ASV)

Sons of God (υιο θεου). In the full sense of this term. In verse 16 we have τεκνα θεου (children of God). Hence no great distinction can be drawn between υιος and τεκνον. The truth is that υιος is used in various ways in the New Testament. In the highest sense, not true of any one else, Jesus Christ is God's Son (8:3). But in the widest sense all men are "the offspring" (γενος) of God as shown in Ac 17:28 by Paul. But in the special sense here only those are "sons of God" who are led by the Spirit of God, those born again (the second birth) both Jews and Gentiles, "the sons of Abraham" (υιο Αβρααμ, Galatians 3:7), the children of faith.