Just as nothing can hide from the radiance, glory and heat of the sun, nothing or no one can hide (or is not seen or touched by) from the glory of the Lord, His statutes, His law, His precepts, His commands, His ultimate love, grace and blessings.
He points out the goodness and the perfection of the Word and praises God for all the ways that it serves, guides, and directs the path of the follower.
I often feel closer to God when I am out in nature and can spend time in awe of His beautiful handiwork but my Bible is a special treasure, when I read the scriptures it is (most times) as if I can't get enough like I am starved for all it has to offer.
As he wonders about the best things of nature, he begins to compare those feelings to the way God's Word compares and the feelings it brings about.
I believe he is asking God to change him in thought as well as deed so that he can live a life that will be pleasing to God in every way.