This question is related to Why does God call Jesus “God” in Hebrews 1:8, unless he is actually God?
In short the answer here is that Psalm 45:7 doesn’t call the king “God”. Just as Hebrews 1:8 does not call Jesus “god”. Hebrews 1:8 is citing Psalm 45 which is mainly addressed to a king of Israel:
Psalm 45:1 My heart overflows with a pleasing theme; I address my verses to the king; my tongue is like the pen of a ready scribe. 2 You are the most handsome of the sons of men; grace is poured upon your lips; therefore God has blessed you forever.
While in Psalm 45 verse 6, it might initially appear (on a quick reading) that this king is addressed as “God”:
6 Your throne, O God, is forever and ever.
The scepter of your kingdom is a scepter of uprightness;
7 you have loved righteousness and hated wickedness.
Therefore God, your God, has anointed you
with the oil of gladness beyond your companions;
So the face of it could look to some readers as if the king is being called “O God”. But a closer look shows that the king is not being called ‘God’:
“Besides me there is no elohim”
The problem is that the Hebrew Bible very clearly and repeatedly says that there is only one God:
“Thus saith the LORD the King of Israel, and his redeemer the LORD of hosts; I am the first, and I am the last; and beside me there is no God.” (Isaiah 44:6)
In Hebrew this is “apart from me there is no elohim”.
Elohim is one of a number of Hebrew nouns which sometimes take apparently plural -im (usually masculine plural) and -oth (usually feminine plural) endings with singular verbs and singular adjectives and pronouns to indicate majesty or greatness. Another well known example of this is Behemoth – the feminine plural of ‘beast’ but with a singular verb, meaning ‘one great beast’, not ‘beasts’ plural.
So according to Isaiah 44:6 there cannot be any elohim, whether a god or gods, apart from the LORD (Yahweh/ Jehovah) himself. There are of course cases where idols are called ‘gods’ in the Hebrew Bible, and the famous passage where corrupt princes are taunted for considering themselves ‘gods’ in Psalm 82:6. These passages were used ironically by the original Hebrew authors, but created an embarrassment for later Jewish translators of the Old Testament into Greek in Egypt’s, Alexandria. Therefore they replaced most of the ‘gods’ verses with ‘angels’ in the text, presumably fearing that readers in the polytheistic environment of Alexandria would be confused.
A different case is found where God tells Moses “I have made you like God to Pharaoh” (Exodus 7:1) – sometimes rendered “like a god to Pharaoh”. Again there is no intention that Moses is actually to be called “God”, so it is not a parallel to “Your throne, O God,”.
Jewish commentaries on Psalm 45:7
Jewish rabbinical commentaries generally read the text as being addressed to God, or meaning that the throne comes from God to the king. The very oldest commentary, the vernacular Aramaic language Targum, has “Your throne of honour, YH, is for ever and ever”.
Ibn Ezra (1089-1167 CE) and the Metzudat David (“The Bulwark of David”, Chief Rabbi of Egypt c. 1540) both read “Your throne is the throne of God”. This is similar to the 1917 JPS translation:
“Thy throne given of G-d is for ever and ever; a sceptre of equity is the sceptre of thy kingdom. 8 Thou hast loved righteousness, and hated wickedness; therefore G-d, thy G-d, hath anointed thee with the oil of gladness above thy fellows.” (1917 Jewish Publication Society)
“Your throne from God is everlasting,” is the translation offered in The Book of Psalms : A New Translation and Commentary by Meir Zlotowitz and Martin S. Rozenberg (2000), along with the explanation “The sense is that the king’s throne has God’s approval because he renders justice from it in accordance with God’s will”.
Other Christian translations:
A few Christian versions following similar translations to the Jewish versions, including:
“Your throne is God’s throne, ever and always; The sceptre of your royal rule, measures right living.” (The Message)
It should be noted though that these are largely highly dynamic or paraphrase versions, where the intention is to translate the meaning as it would have been understood by Jewish readers, not a word-for-word translation of the Hebrew grammar.
A change of addressee?
Most of the readings above take the addressee in verse 6 to continue to be the king, and therefore analyse the “your throne, O God” from that standpoint, as the king being agent of God on God’s throne.
There is however an alternative reading; that there is simply an interjection, a change of subject, a call to God, just as the Psalm four verses later changes the addressee to address the bride
“ 9 daughters of kings are among your ladies of honor; at your right hand stands the queen in gold of Ophir. 10 Hear, O daughter, and consider, and incline your ear: forget your people and your father’s house, 11 and the king will desire your beauty. (Psalm 45:9-11)
“O daughter” is evidently not addressed to the king, just as when verse 16 suddenly switches back to addressing the king; “In place of your fathers shall be your sons; you will make them princes in all the earth.” In 16 the addressee is clearly no longer the bride.
Conclusion – whose throne is it anyway?
Most Christian readers probably read Psalm 45:6 already being more familiar with Hebrews 1:8, but this would not have been the way the original readers read it. In terms of understanding both Psalm 45:6 and Hebrews 1:8 it would be a case of putting the cart before the horse to read from an assumption about what Hebrews 1:8 means to many Christians, back into what Psalm 45:6 meant (and means) to Jewish reader.
Another complicating factor is that Hebrews 1:8 does not quote the Hebrew Bible text of Psalm 45:6, but the Greek Septuagint translation. It is likely that the author of Hebrews himself knew both the original Hebrew and the Greek version, but it is unlikely that his Greek-speaking Jewish readers had any idea what the original Hebrew of Psalm 45 said. What however the Hebrew-speaking Jews reading the Hebrew version, and Greek-speaking Jews reading the Septuagint version would have in common as a starting point was the understanding that the Kingdom and the Throne belonged to God, not to the king:
Of all my sons–and the LORD has given me many–he has chosen my son Solomon to sit on the throne of the kingdom of the LORD over Israel. (1 Chronicles 28:5)
So Solomon took the throne of the LORD in place of his father, David, (1 Chronicles 29:23)
The above references to Solomon sitting on the throne of the LORD are particularly relevant to Psalm 45 as it is generally classed as one of the ‘bridal psalms’ which are traditionally linked with Solomon not David. As such “Your throne, O God, is forever and ever” does not refer to the king at all, since it was not really his throne, and no king – not Solomon, nor David, would continue forever and ever. The throne represents God.
So in conclusion, what should we say? Is the king of Israel called “O, God” in Psalm 45? It is possible, yes. Though this is not a statement such as “You, O King, are God” – that reading is only inferred, not stated. Christians, Trinitarian Christians in particular, sometimes insist that “the text says so, in black and white”. But it doesn’t, otherwise we wouldn’t be discussing the question.
Given the consistent position of the Hebrew Bible (Isaiah 44:6 etc), the “You, O King, are God” reading is not likely, or even natural, since it would be the only example in the Hebrew Bible of any man being called, without irony, “O, God”. And what purpose does it serve in the Psalm? Why would the Psalmist suddenly teach that a king of Israel, for example Solomon, was himself ‘God’, when the Bible – including accounts of Solomon’s coronation – repeatedly teaches that the throne was not even his own.