Romans 8:16

αὐτὸ τὸ πνεῦμα κ.τ.λ. The absence of a conjunction suggests that this is, in some sort, an explanation of the preceding phrases (rather than an analysis of the consciousness, as S. H.). If this be so, then the idea is that the Spirit, which mates man’s spirit a spirit of sonship, by inspiring this cry of man’s spirit joins in testifying to the true relation to GOD.

τέκνα θεοῦ. Cf. Philippians 2:15; otherwise only in Joh.; cf. esp. 1 John 3:2. On the other hand Joh. never uses υἱοὶ θεοῦ of men (cf. Matthew 5:9; Matthew 5:45; Luke 6:35; Luke 20:36; Revelation 21:7; Hebrews 2:10; Hebrews 12:5 f.; here 14, 19, Romans 9:26 (qu.); Galatians 3:26; Galatians 4:6-7 only). υἱός rather describes the dignity and privilege of the son, τέκνον the sharing in the life of the father; cf. Westcott, Epp. Joh., pp. 120, 121. So here τέκνα is substituted, as the ground of κληρονομία, because the main thought here is of the life possessed by Christians, not of the privilege.