ὃς ὢν ἀπαύγασμα τῆς δόξης καὶ χαρακτὴρ τῆς ὑποστάσεως αὐτοῦ, φέρων τε τὰ πάντα τῷ ῥήματι τῆς δυνάμεως αὐτοῦ, καθαρισμὸν τῶν ἁμαρτιῶν ποιησάμενος ἐκάθισεν ἐν δεξιᾷ τῆς μεγαλωσύνης ἐν ὑψηλοῖς, 4 τοσούτῳ κρείττων γενόμενος τῶν ἀγγέλων ὅσῳ διαφορώτερον παρ᾽ αὐτοὺς κεκληρονόμηκεν ὄνομα.First, the participles: the sequence is present, present, aorist, aorist. Two states viewed as ongoing: (1) Christ's being the radiance of God's glory and the impress of His being, and (2) His carrying the universe by His powerful word. Two actions (or states) viewed as past: (1) the accomplishment of purification of sins, and (2) being better than the angels.
The contrast matters to the writer. What Christ was as to His essence is timeless and ongoing (cf. 13:8), and this gives meaning to His eternal Person and His historical work.
But this purification of sins was an historical event, done once for all (cf. 7:27; 9:12; 10:10), never to be repeated.
Then note the two finite verbs in verse four: ἐκάθισεν, whose importance I discussed in the previous post; and κεκληρονόμηκεν.
It isn't often that a man's thought and eloquence are as well-matched as they are in this man. One thinks of Spurgeon... and very few others.