φέρων τε τὰ πάντα τῷ ῥήματι τῆς δυνάμεως αὐτοῦ,
καθαρισμὸν τῶν ἁμαρτιῶν ποιησάμενος
ἐκάθισεν ἐν δεξιᾷ τῆς μεγαλωσύνης ἐν ὑψηλοῖς,
What is the effect of the middle ποιησάμενος? The other participles and verbs are active...ὤν, φέρων, ἐκάθισεν. Is there any way that ποιησάμενος could be read as passive? The passage talks about the supremacy of the Son over angels, so the active sense fits in the context, So would you categorize this as an intensive use with no sense of a reflexive? e.g. 'He himself made the purification (offering)" versus "He made himself the purification (offering)" - or somewhere in between?
Job 7.21 καὶ διὰ τί οὐκ ἐποιήσω τῆς ἀνομίας μου λήθην καὶ καθαρισμὸν τῆς ἁμαρτίας μου; νυνὶ δὲ εἰς γῆν ἀπελεύσομαι, ὀρθρίζων δὲ οὐκέτι εἰμί.
2 Mac 2.16 Μέλλοντες οὖν ἄγειν τὸν καθαρισμὸν ἐγράψαμεν ὑμῖν, καλώς οὖν ποιήσετε ἄγοντες τὰς ἡμέρας.
Ex 29.36 καὶ τὸ μοσχάριον τῆς ἁμαρτίας ποιήσεις τῇ ἡμέρᾳ τοῦ καθαρισμοῦ καὶ καθαριεῖς τὸ θυσιαστήριον ἐν τῷ ἁγιάζειν σε ἐπ̓ αὐτῷ καὶ χρίσεις αὐτὸ ὥστε ἁγιάσαι αὐτό.
BDAG gives the glosses (1) cleansing from cultic impurity, purification (2) cleansing from inward pollution, purify, fig. extension of 1 (TestLevi 14:6 v.l.) 1 Cl 60:2 (s. καθαρίζω 3bα). κ. τῶν ἁμαρτιῶν ποιεῖσθαι bring about purification from sin (cp. Job 7:21) Hb 1:3. Cp. 2 Pt 1:9. Thus BDAG just abstracts the word with no reference to a ritual offering.
But LSJ says καθαρισμός is late for καθαρμός
A. cleansing, purification, from guilt, “νίψαι καθαρμῷ τήνδε τὴν στέγην” S.OT1228: hence, purificatory offering, atonement, expiation, “καθαρμὸν τῆς χώρης ποιέεσθαί τινα” Hdt.7.197: freq. in pl., “μύσος ἐλαύνειν καθαρμοῖς” A.Ch.968 (lyr., dub. l.), cf. Th. 738, Eu.277, 283, Berl.Sitzb.1927.156 (Cyrene): sg., S.OT99; θοῦ νῦν καθαρμὸν δαιμόνων make an offering to avert their wrath, Id.OC466; “καθαρμὸν θύειν” E.IT1332; “λύσεις τε καὶ καθαρμοὶ ἀδικημάτων” Pl.R. 364e; ὁ περὶ τὴν διάνοιαν κ. Id.Sph.227c; κ. ποιεῖσθαι τῆς δυνάμεως, Lat. lustrare exercitum, Plb.21.41.9, Plu.Caes.43; of the Roman lustrum, D.H.4.22; κ. ὅπλων, σάλπιγγος,= Lat. armilustrium, tubilustrium, Lyd.Mens.4.34,60.