1:15 image. This is a clear affirmation of the absolute deity of Jesus Christ. Christ is whatever God is—spiritual, omnipotent, omniscient, holy—all the attributes of the eternal God. The word “image” (Greek eikon) conveys this meaning. Jesus Christ represents—indeed is—“very God of very God.” Jesus said, “He that hath seen me hath seen the Father” (John 14:9). God in His essence is invisible (John 1:18) but we see all His attributes in Christ.
1:15 firstborn. Christ is “the firstborn,” not in the sense that He ever came into existence from a prior condition of non-existence, but rather as eternally proceeding from the Father, the only begotten Son, always manifesting the Father. This truth can be called the doctrine of eternal generation. He is from eternity to eternity in relation to the Father as a Son. Some are sons of God by creation (e.g., angels; see Job 1:6), and we can become sons of God by adoption (e.g., Romans 8:14-15), but He is the Son, by eternal generation (or eternal relation) the only-begotten of the Father. He also has the right of inheritance of the firstborn (Hebrews 1:2) and is “the firstborn from the dead” (Colossians 1:18).