In hope of eternal life, which God, that cannot lie, promised before the world began; In hope of eternal life - In expectation of a state of being and well being which should last through eternity, when time should be no more. This includes, not only the salvation of the soul and its eternal beatification, but also the resurrection of the body. This was a point but ill understood, and not very clearly revealed, under the Mosaic law; but it was fully revealed under the Gospel, and the doctrine illustrated by the resurrection and ascension of Christ.
Which God, that cannot lie, promised - We have often seen that the phrase, the foundation of the world, means the Jewish economy, and, before the foundation of the world, the times antecedent to the giving of the law. This is evidently the meaning here. See 2 Timothy 1:9-11.
Supposing the word αιωνιων in this verse to signify eternal, says Dr. Macknight, the literal translation of προ χρονων αιωνιων would be, before eternal times; but that being a contradiction in terms, our translators, contrary to the propriety of the Greek language, have rendered it before the world began, as Mr. Locke observes on Romans 16:25. The true literal translation is before the secular times, referring us to the Jewish jubilees, by which times were computed among the Hebrews, as among the Gentiles they were computed by generations of men. Hence, Colossians 1:26, The mystery which was kept hid απο των αιωνων και απο των γενεων, from the ages and from the generations, signifies the mystery which was kept hid from the Jews and from the Gentiles.