In Hebrews 1:10–12, the author of the Epistle to the Hebrews quotes Psalms 102:25–27 (101:26–28)1 of the Greek Septuagint.
1 There is a difference in how the Greek Septuagint of Psalms is traditionally numbered versus how most English translations of the Psalms are numbered. For example, Psa. 102:1 in the King James Version corresponds to Psa. 101:1–2 of the Greek Septugaint. In this question, I will be using this verse numbering format:
Psa. X (Y), where X is the verse numbering of the King James Version (including the Hebrew text of the Old Testament), and Y is the verse numbering of the Greek Septuagint. For example: Psa. 102:1 (101:1–2).
10 καί σὺ κατ᾽ ἀρχάς κύριε τὴν γῆν ἐθεμελίωσας καὶ ἔργα τῶν χειρῶν σού εἰσιν οἱ οὐρανοί 11 αὐτοὶ ἀπολοῦνται σὺ δὲ διαμένεις καὶ πάντες ὡς ἱμάτιον παλαιωθήσονται 12 καὶ ὡσεὶ περιβόλαιον ἑλίξεις αὐτούς ὡς ἱμάτιον καὶ ἀλλαγήσονται σὺ δὲ ὁ αὐτὸς εἶ καὶ τὰ ἔτη σου οὐκ ἐκλείψουσιν
Psalms 102:25–27 (101:26–28), LXX
25 κατ᾽ ἀρχὰς σύ κύριε τὴν γῆν ἐθεμελίωσας καὶ ἔργα τῶν χειρῶν σού εἰσιν οἱ οὐρανοί 26 αὐτοὶ ἀπολοῦνται σὺ δὲ διαμενεῗς καὶ πάντες ὡς ἱμάτιον παλαιωθήσονται καὶ ὡσεὶ περιβόλαιον ἀλλάξεις αὐτούς καὶ ἀλλαγήσονται 27 σὺ δὲ ὁ αὐτὸς εἶ καὶ τὰ ἔτη σου οὐκ ἐκλείψουσιν
It is obvious that the author of the Epistle to the Hebrews is not quoting from the Hebrew scriptures because Psa. 102:25 (101:26) in the Hebrew does not have any word equivalent to κύριε, which occurs in both Psa. 101:26 in the LXX and Heb. 1:10 in the Greek NT.
Now, encountering κύριε (lemma κύριος) in the Greek New Testament, we might assume that it simply means “lord,” as in the master of a servant. This is how it is commonly used in reference to the Lord Jesus Christ in the New Testament, since Christians are his servants.2
2 1 Cor. 7:22
But, of course, this was not its common use in the Septuagint which was translating the Hebrew scriptures of the Old Testament. Instead, κύριος was most often used to translate the Hebrew words אֲדֹנָי (Adonai), a title of God, and יהוה (Yahveh), the Tetragrammaton, or name of God.
Psalms 102:1–28 (101:1–29 LXX)
The lemma κύριος occurs 10 times in the LXX of Psalms 102 (101).3 Of these 10 occurrences, it occurs 3 times in the vocative, including Psa. 102:25 (101:26) (quoted in Heb. 1:10).4
3 Psa. 102:1 (101:1, 101:2), 102:12 (101:13), 102:15 (101:16), 102:16 (101:17), 102:18 (101:19), 102:19 (101:20), 102:21 (101:22), 102:22 (101:23), 102:25 (101:26)
4 Psa. 102:1 (101:2), 102:12 (101:13), 102:25 (101:26)
While the Hebrew of Psa. 102:25 (101:26) does not have a corresponding word that translates into Greek as κύριε, if we examine the other 2 occurrences of the vocative κύριε in Psa. 102:1 (101:2) and 102:12 (101:13), we find that κύριε is used to translate the Tetragrammaton יהוה.
It is reasonable to conclude that the author of the Septuagint had the Tetragrammaton in mind when he wrote the vocative κύριε in Psa. 102:25 (101:26) of the LXX. The context of Psa. 102:25 (101:26) has no other subject in it that could be identified by κύριε except God Himself. The subject “laid the foundation of the earth,” an act which is explicitly ascribed to God elsewhere.5
5 Job 38:4; Psa. 24:1–2, 78:69, 89:11, 104:5; Pro. 3:19; Isa. 51:13, 51:16; Zec. 12:1
The author of the Epistle to the Hebrews quotes 102:25–27 (101:26–28) of the LXX in Heb. 1:10–12. Moreover, he has “the Son” (i.e., the Lord Jesus Christ) in mind when he does so, as indicated by the phrase “But to the Son” in Heb. 1:8. The author repeatedly switches between contrasting the angels (Heb. 1:5–7; 1:13–14) with the Son (Heb. 1:8–12) in order to demonstrate the superiority of the Son over the angels. In the process, the author applies Heb. 1:10 to the Son, and by doing so, he seems to equate the Son with “the Lord” (i.e., Yahveh) who laid the foundation of the earth.
Is the vocative κύριε in Psa. 102:25 (101:26), wherein the subject “laid the foundation of the earth,” a reference to Yahveh?
If so, by quoting Psa. 102:25 (101:26) and applying it to the Son, is the author of the Epistle to the Hebrews thereby implying that the Son is Yahveh?