NET

3 The Son is the radiance of his glory and the representation of his essence, and he sustains all things by his powerful word, and so when he had accomplished cleansing for sins, he sat down at the right hand of the Majesty on high.

Darby

3 who being [the] effulgence^D8971 of his glory and [the] expression of his substance^D8972, and upholding all things by the word of his^D8973 power, having made^D8974 [by himself] the purification of sins, set himself down on the right hand of the greatness on high,

Darby Bible Notes

effulgence - That which fully presents the glory which is in something else. Thus light makes us know what the sun is; the tabernacle, what the pattern in the mount was. substance - Clearly 'substance,' 'essential being,' not 'person.' It is of God, not of the Father. his - That is, his own, the Son's. made - The form (middle) of the verb here, has a peculiar reflexive force, 'having done it for himself.' Though we, as alone the sinners, have the profit, yet the work was done within his own person and work, without us, as when a man journeys, and so when he makes a person his friend, his wife.

KJV

3 Who being the brightness of [his] glory, and the express image of his person, and upholding all things by the word of his power, when he had by himself purged our sins, sat down on the right hand of the Majesty on high;