Happiness Is the End of the Creation
Jonathan Edwards from Miscellanies #3:
Happiness is the end of the creation ... because the end of the creation is that the creation might glorify [the Creator]. Now what is glorifying God, but a rejoicing at that glory he has displayed? An understanding of the perfections of God, merely, cannot be the end of the creation; for he had as good not understand it, as see it and not be at all moved with joy at the sight. Neither can the highest end of the creation be the declaring God's glory to others; for the declaring God's glory is good for nothing otherwise than to raise joy in ourselves and others at what is declared.
In other words, it would be meaningless for God to create the universe if the highest purpose of the creation was merely to understand or to declare his perfections. Rather, it is when the creation is made happy in understanding and declaring his perfections that God gets the most glory.
Check out John Piper's seminar "Desiring God" (or read the book) to see the biblical foundations for this truth.