Hebrews 6:19

Greek (WH): ἣν ὡς ἄγκυραν ἔχομεν τῆς ψυχῆς, ἀσφαλῆ τε καὶ βεβαίαν καὶ εἰσερχομένην εἰς τὸ ἐσώτερον τοῦ καταπετάσματος,

"We have this as a sure and steadfast anchor of the soul, a hope that enters into the inner place behind the curtain" (Hebrews 6:19 ESV)

Smyth's Greek Grammar: 2989. Relative ὡς as, how is originally an ablative (in which way) from the relative stem [ιγλιδε]ο-, whence come also ὅς, ἥ, ὅ. For the -ς, see 341. Relative ὡς has various uses as an adverb or a conjunction, all of which represent the primitive meaning.

The occurrence of ἣν tells us that ὡς functions as a relative in Hebrews 6:19.

ἄγκυραν signifies an anchor or hook (Acts 27:29-30, 40).

Do the words ἀσφαλῆ τε καὶ βεβαίαν modify "anchor" or "hope"?

Christopher W. Cowan answers:

While ἄγκυραν is the closest noun in agreement, commentators have frequently found the image of an anchor entering through the curtain into the heavenly holy place to be problematic.96 As a result, many have argued that either (1) “sure and steadfast” are modifying “anchor,” while the participle, “enters,” reaches back to modify “hope,”97 or (2) all three attributes modify “hope.”98 But such concerns seem unnecessary. Of course anchors do not reach up into the heavens, nor do they enter into the holy place! But the imagery accomplishes what the author intends: to illustrate and reinforce his message of a hope that is firmly secured.99 Moreover, attempts to argue that the attributes modify “hope” but not “anchor” seem hollow since the author identifies the two—hope is “like an anchor.”100

See Cowan, “Confident Of Better Things”: Assurance Of Salvation In The Letter To The Hebrews, page 148 (2012 Ph.D. Diss.).

Compare https://fosterheologicalreflections.blogspot.com/2014/12/jesus-entered-within-curtain-how.html