3:16 mystery. The “mystery” may be difficult for the ungodly world to comprehend, but it has been revealed to all who receive Christ (compare Ephesians 1:9; 3:3,9; 5:32).
3:16 manifest in the flesh. Before “the Word was made flesh” (John 1:14), “no man hath seen God at any time” (John 1:18). The Father and the Spirit are still omnipresent and therefore invisible, but the Son has finally become Son of man as well as Son of God, and will henceforth and forever be in His glorified human body.
3:16 seen of angels. Evidently God was for the very first time “seen of angels” when they saw Him as a babe in the manger at Bethlehem (Luke 2:9-13). Before, He had been invisible to them as well as to man, “dwelling in the light which no [one] can approach unto” (I Timothy 6:16): In this verse, “man” is not in the original. No one may see God in His essential glory, even though He has occasionally assumed human form in “theophanies.”
3:16 Gentiles. “Gentiles” is the same as “nations.”