The Psalmist wrote down what his heart was inspired to write...although it's doubtful he could possibly have known the full implications of the words.
It is easy for us to assume that just because we grasp the truth of what a God has said in our immediate context or circumstance that we have somehow apprehended the fullness of that truth, the bigger picture flowing from the purposes of God's heart - but we rarely do, that is the domain of prophetic gifting.
As an aside, this is why three things are crucial in the church in this respect:
> Seek prophetic gifting and ministry within and among Gods people
> Learn to test the spirits
> Learn to recognise / perceive prophetic gifting in others
> Do not despise prophecy
Anyway, back to the Psalmist....
'Blessed is the nation whose God is the Lord, the people he chose for his inheritance.' (Psalm 33:12 )
How could he have grasped that there would be such a head spinning radical 'new covenant' relationship down the line?
That this relationship,based on the sacrifice of God Himself, would redefine what it is to be a 'nation under God'?
That the whole concept of the 'holy nation' that God has chosen - and the qualification for entry and residence would be so dramatically changed?
How could he grasp what it would mean to be part of His inheritance?
But to us, the church, the fullness of these truths have been revealed by His Spirit.
How tragic then, that those of us who live in the fullness of a truth that the original writer could not in his wildest dreams have imagined, can often take it so much for granted, can be so blasé about such game changing, eternity altering, life affirming, mind renewing, Spirit empowered truth.
In the words of the Matt Redman song 'Mercy' 'may we never lose the wonder' but, Lord, if we do, or are in danger of doing so, please restore to us this wonder.