but his delight is in the law of the LORD, and on his law he meditates day and night. (ESV)
The Psalmist continues his description of the man who is truly "blessed." We discovered in the previous verse that the idea of being "blessed" means to have full contentment in God. It is not based on circumstances. It is not about accumulating material possessions or even having good relationships. The psalmist talked about the things a blessed man runs from. Now he turns to what a blessed man runs to.
A blessed man delights in the law of the Lord. Consider how we tend to view God's Law. Do we usually think of it with delight? Assuredly, the sinful man looks at God's Law and all he sees is restrictions on his "freedom," not realizing that the only way freedom can be enjoyed is with boundaries set in place by a loving Law-Giver.
God the Father is a loving Law-Giver. The law that he has given to us is for our good and for his glory. A simple glance at the ten commandments, the cornerstone of God's Law, shows that God cares first and foremost how we care about him, and then secondarily about how we care about our fellow man. God loves. His Law is evidence of that love.
A blessed man not only delights in God's Law, but he meditates on his law day and night. There is a difference between dutifully reading God's Law and meditating on it. God's Word. I encourage you to do both! You must read it so that you can meditate on it. Once you have grown to know and memorize the Word of God you will find delight in it. It is a joy to your spirit.
Do you want to be blessed? Do you want to have the continual joy that will get you through any trials? Delight in God's Law. He is a loving Law-Giver. Meditate on God's Law. It is a joy.