The Book of Hebrews is a magnificent literary work. It is a written sermon, a homily, from a 1st generation preacher whose identity only God knows. The writer of Hebrews captures the attention of his audience (whether through a reader in a 1st century church or the individual reader today) with an amazing introduction (Heb. 1:1-14) on the topic of the superiority of Christ over all things. In the eighth verse we find a stunning comment which serves to support the New Testament teaching that Jesus of Nazareth is true deity. One can read the first chapter for the larger context, below I include the immediate context:

7 Of the angels he says,

“He makes his angels winds,
and his ministers a flame of fire.”

8 But of the Son he says,

“Your throne, O God, is forever and ever,
the scepter of uprightness is the scepter of your kingdom.
9 You have loved righteousness and hated wickedness;
therefore God, your God, has anointed you
with the oil of gladness beyond your companions.”

With regard to Jesus (“the Son,” v. 8) the writer of Hebrews cites Psalm 45:6-7 which begins “Your throne, O God, is forever and ever.” The Greek text lists only one variant reading. This is at the end of the verse where a few texts have “his kingdom” or “the kingdom” rather than “your kingdom.” The ESV’s reading received a {B} rating (one step higher than the {C} rating in the previous, 3rd edition) from the United Bible Society., which is a very solid score for a variant. Regardless, whichever reading you give to the end of verse 8, it does not change the point at hand: the writer of Hebrews calls Jesus “God.”
Verse 8 begins,

8 But of the Son (υἱόν) he says,

“Your throne, O God (θεὸς), is forever and ever,

There is no doubt the throne of God is occupied by the triune God, it can therefore be justly occupied by the Father, Son or Spirit. The Son, in this instance is identified as the one who possesses the throne, and the royal privileges which attend the one who sits upon the throne. Certainly the big point of this passage is that Jesus is greater than the angels (v. 5, 7, 13). And who is truly greater than the angels but God?

Context of Psalm 45

Psalm 45 is a “love song” (see title), “crafted for the wedding of the king.”1 The psalm is divided into four parts, the first “describes the inspiration and the handsomeness of the king,” (vv. 2-3) the second describes the king as a groom (vv. 4-9), the third is “an address encouraging the bride to joy and submission, and in praise of the bride” (vv. 10-15), and the final section the king is addressed “with an expression of hope for the endurance of his dynasty and the effectiveness of his rule” (vv. 16-17).2

While it has been suggested that the Hebrew of verse 7 (verse 6 in English translations,כִּסְאֲךָ֣ אֱ֭לֹהִים עוֹלָ֣ם וָעֶ֑ד “Your throne, O God”) could be “Your throne is God’s for ever and ever” or “Your throne is like God’s throne,” or “The everlasting God has enthroned you,” These possibilities are do not do adequate justice to the punctuation and syntax of the Masoretic Text.3

In favor of the Masoretic reading, the Septuagint offers the following rendering of the Hebrew,

ὁ θρόνος σου, ὁ θεός, εἰς τὸν αἰῶνα τοῦ αἰῶνος,

ὁ θρόνος σου, (literally, “the throne your”) means “your throne.” ὁ θεός, “Oh God.” εἰς τὸν αἰῶνα τοῦ αἰῶνος, “is forever and ever.” The last phrase “εἰς τὸν αἰῶνα τοῦ αἰῶνος” is used similarly in Psalm 111:5, 8, 10; 112:3, 9; 145:1, 2, 21 and other places.

Septuagint (LXX) of Psalm 45:6

It is also noteworthy that this phrase, when cited by the writer of Hebrews, is lifted from the LXX as a direct quote:

ὁ θρόνος σου ὁ θεὸς εἰς τὸν αἰῶνα τοῦ αἰῶνος,

The notable difference is the progression in theological sophistication. In the time of the Psalmist the psalm was composed for an occupant of the Davidic throne. After God revealed himself in the person of Jesus through his earthly life and ministry, and ultimately through his death, resurrection, and ascension, the writer of Hebrews recognized that Jesus was the ultimate fulfillment of this passage.

Conclusion

There is very little room to for an honest, academic altering of the translations offered by virtually every major translation of the Bible. The throne of God is the Son’s throne, which will endure forever and ever!