“Whereby, when ye read, ye may understand my knowledge in the mystery of Christ)”
King James Version (KJV)
3:2 The dispensation of the grace of God given me in your behalf - That is, the commission to dispense the gracious gospel; to you gentiles in particular. This they had heard from his own mouth.
3:3 The mystery - Of salvation by Christ alone, and that both to Jews and gentiles. As I wrote before - Namely, #Eph 1:9|,10; the very words of which passage he here repeats.
3:5 Which in other - In former, ages was not so clearly or fully made known to the sons of men - To any man, no, not to Ezekiel, so often styled, son of man; nor to any of the ancient prophets. Those here spoken of are New Testament prophets.
3:6 That the gentiles are joint - heirs - Of God. And of the same body - Under Christ the head. And joint - partakers of his promise - The communion of the Holy Ghost.
Eph 3:4 Whereby, when ye read, ye may understand my knowledge in the mystery of Christ. When they read what he wrote above (before), and what he writes now, they can perceive his knowledge of this mystery.