Jesus spoke of the difference between Shepherds and hired hands. He was referring to the men who lead the flocks of God, by this analogy to Pastors. His insinuation was that the "true Shepherds" would watch over the flock of God with their heart and soul, while the "hired hands" were only concerned with making a living. It can be similar to the way football players play football. When a player has a contract, he knows the team has a set amount invested in him, whether he gets hurt or not. If he gets hurt he may not be able to play, but he'll still get paid. He tends to give it his all, to improve the demand for his game. Meanwhile, players who are still looking to make a contract will just be out of the game and out of a job if they are injured and can't play. They are less likely to take risks in a game. Jesus was speaking of the concern a shepherd would have for his sheep, if they were his and his livelihood depended on them, rather than the man just hired as a day laborer who would move on to the next job if something happened to the sheep.
     This idea of leadership extends to nations, as well as businesses. Typically, Kings rule for life. They have a vision for the Kingdom, and hope to pass the crown down through generations of their sons. They have much more at stake than a President who only has the office for one or two four year terms. The first term's vision is often to get re-elected. The second term's vision is to repay the folks who got him there, and grease as many palms as possible to ensure his rise to wealth when leaving the office. There is no carry over, no personal investment in the country, no heritage to leave for future generations in the minds of many career politicians.
     It was not so in the Kingdom of Israel, particularly in the reign of King David, who was promised by God Himself that the dominion of his throne would endure forever. Many of the Psalms were written by David, though people disagree about how many. One which is certain to have been written as his last, according to tradition, and even says that it was written as a prayer for Solomon as he was taking over the throne and David was dying, is Psalm 72. Yet, some still say it was written by Solomon, though that contradicts the internal evidence. This Psalm is a lovely prayer for Solomon as a leader of the people, and more than that, for the nation to endure as a godly people. 
     Keep in mind that the Psalms were grouped into 5 books, much like CD Albums, and were not grouped in order of writing. Many include the authors' names, and the occasion of writing, as does "track 72," in the second "album" that extends from 42 to 72. This "album," o collection of Psalms is called the Exodus section, because in it they sing of the nation in ruin, and call out to God for deliverance. They speak of how God is able to rescue His people. Psalm 42 begins by crying out for God’s presence in a dry wilderness experience. The singers plead with God for deliverance from enemy oppression. The book finishes with Track 72, a prayer of David for Solomon. The final verses also praise God for His power and might, and His glory. Also, notice that this book (album,) like the first three books of Psalms (albums) ends with a double "Amen, and Amen."The last two books end with "Amen. Praise you the Lord." 
     I've given quite a bit of background for a purpose. This reveals a structure to the Psalms. The structure points out the purpose. Nothing God has done was done without purpose. So, now to wander gingerly into this jewel of a Psalm, which was after all, David's last song. I will paste the song in below, and substitute a few words as the whim strikes me. Substitutions are bold capped, and extra inserted words are in bold red caps. If you are troubled by my substitutions, don't think of them as taking license with the Scripture, but rather applying them to the here and now.