John Piper wrote:
It is not surprising, then, that Jonathan Edwards struggled earnestly and deeply with the problem that stands before us now. How can we affirm the happiness of God on the basis of His sovereignty when much of what God permits in the world is contrary to His own commands in Scripture? How can we say God is happy when there is so much sin and misery in the world?
Edwards did not claim to exhaust the mystery here. But he does help us find a possible way of avoiding outright contradiction while being faithful to the Scriptures. To put it in my own words, he said that the infinite complexity of the divine mind is such that God has the capacity to look at the world through two lenses. He can look through a narrow lens or through a wideangle lens.
When God looks at a painful or wicked event through His narrow lens, He sees the tragedy of the sin for what it is in itself, and He is angered and grieved: “I have no pleasure in the death of anyone, declares the Lord GOD” (Ezekiel 18:32).- Desiring God: Meditations of a Christian Hedonist page 39
But when God looks at a painful or wicked event through His wide-angle lens, He sees the tragedy of the sin in relation to everything leading up to it and everything flowing out from it. He sees it in relation to all the connections and effects that form a pattern, or mosaic, stretching into eternity. This mosaic in all its parts—good and evil—brings Him delight.5
John Piper also wrote:
God's Happiness Is A Great Part Of His Glory- God is the Gospel page 100
In 1 Timothy 1:11 Paul focuses on the gospel as "the glory of the blessed God." The word translated "blessed" in this phrase (makarivou) is the same one used in the beatitudes of Jesus in Matthew 5:3-11. "Blessed are the poor in spirit, for theirs is the kingdom of heaven. Blessed are those who mourn, for they shall be comforted. Blessed are the meek, for they shall inherit the earth." And so on. The word means "happy" or "fortunate." Paul himself uses it in other places to refer to the happiness of the person whose sins are forgiven (Rom. 4:7) or the person whose conscience is clear (Rom. 14:22). It is astonishing that only here and in 1 Timothy 6:15 in the entire Old Testament and New Testament does the word refer to God. Paul has clearly done something unusual, calling God makarios, happy.
We may learn from the phrase "the glory of the happy God" that a great part of God's glory is his happiness. It was inconceivable to the apostle Paul that God could be denied infinite joy and still be all-glorious. To be infinitely glorious was to be infinitely happy. He used the phrase, "the glory of the happy God," because it is a glorious thing for God to be as happy as he is. God's glory consists much in the fact that he is happy beyond all our imagination.
John Piper wrote an entire book on the Blessedness or Happiness of God titled, The Pleasures of God: Meditations on God's Delight in Being God.
I believe (rightly or wrongly) that the first chapter has been posted online HERE.
In Piper's various books he argues that God's happiness and God-centeredness isn't selfish but the very foundation for our own happiness. There's no space or time to elaborate in Piper's argument, but here's a distillation of it from a quote by Sam Storms.
God created us so that the joy he has in himself might be ours. God doesn't simply think about himself or talk to himself. He enjoys himself! He celebrates with infinite and eternal intensity the beauty of who he is as Father, Son, and Holy Spirit. And we've been created to join the party!
Here's a link to book 1 chapter 19 of John Gill's A Body of Doctrinal Divinity:
Of The Joy Of God