Hath in these last days spoken unto us by his Son, whom he hath appointed heir of all things, by whom also he made the worlds;
In these last days. In 'Aleph (') A B Delta х ep' (G1909) eschatou (G2078)], 'at the last part of these days.' The rabbis divided time into 'this age' and the 'age to come' (Hebrews 2:5; Hebrews 6:5). The days of Messiah were the transition period, or 'last part of these days' (in contrast to "in time past," Hebrews 1:1); the close of the existing, and beginning of the final, dispensation; of which Christ's second coming shall be the consummation.
By his Son - Greek, 'IN (His) Son' (John 14:10): the true 'prophet' of God. 'His majesty is set forth:
(1) Absolutely, by "Son," and by three glorious predicates, "whom He hath appointed," "by whom also He made the worlds," "who ... sat down on the right hand of the Majesty on high." Thus His course is described from the beginning of all things down to the goal (Hebrews 1:2-3).
(2) Relatively, in comparison with the angels, Hebrews 1:4: the confirmation follows; the name "Son" is proved at Hebrews 1:5; the "heirship," Hebrews 1:6-9; the "making the worlds," Hebrews 1:10-12; the "sitting at the right hand" of God, Hebrews 1:13-14.'
His heirship follows His sonship, and preceded His making the worlds (Proverbs 8:22-23; Ephesians 3:11). As the first begotten, He is heir of the universe (Hebrews 1:6), which He made instrumentally, Hebrews 11:3, where "by the word of God" answers to "by whom" (the Son of God) here (John 1:3). Christ was "appointed" (in God's eternal counsel) to creation as an office; the universe so created was assigned to Him as a kingdom. He is "heir of all things" by right of creation, and especially by redemption. The promise to Abraham, that he should be heir of the world, had its fulfillment, and will have it more fully, in Christ (Romans 4:13; Galatians 3:16; Galatians 4:7).
Worlds - the inferior and the superior (Colossians 1:16): х aioonas (G165)] ages, with all things and persons belonging to them: the universe, including all space and ages, and all material and spiritual existences. He not only appointed His Son heir of all things before creation, but He also (better than "also He") made by Him the worlds.