Surely you have granted him unending blessings and made him glad with the joy of your presence.
The 2011 version of the NIV quoted above seems to me to have weakened the sense of verse 6 from that in the 1984 edition, and of other more recent translations like the English Standard Version and older such as the Authorised Version. David had enjoyed the temporal blessings the Lord had given him in granting the desire of his heart, a long life, victory over enemies and so on and here now the praise turns to “eternal blessings” or of God blessing him “forever” both of which seem stronger to me than “unending blessings” used above. OK I’m splitting hairs but it’s the confidence expressed here that God’s blessing of David will most certainly spill over into eternity that is central I think.
For the present though he enjoyed the presence of God which gladdened his heart. It’s funny in the sense of peculiar how your life turns over in 10 or 15 years. A dozen years ago when our house was full with the family and TV’s, radio’s and hair dryers (not for me of course) were going endlessly I found that I could often pray better in the church building than at home, the quietness just seemed conducive to prayer. Often though prayer fizzled out after a time and I found myself just sitting without saying or necessarily thinking anything. What I thought was a lack of concentration troubled me until I realised that it was prayer in a different sense, I was enjoying the presence of God and that was spiritually refreshing.
When we are nervous or trying to impress someone we tend to chatter on or feel that we have to fill every silence with words. Silence makes us uncomfortable yet, when two people are comfortable in each other’s presence and know one another well they can readily enjoy their company in silence. Perhaps when we have said what we need to say in terms of praise and confession and supplication we need to learn to enjoy the presence of God in silence, a presence which makes us glad with joy.
Give thanks to God for the everyday blessings you have received and for the eternal spiritual blessings that are ours in Christ. Perhaps meditate on these blessing and on his word and then enjoy his presence.