There are many different names and titles for God in the Bible, just as there are many different names and titles for Jesus in the New Testament. Because God is eternal and infinite, transcending all the limitations of our human experience, we can only try to increase our understanding of God by concentrating moment by moment on the way in which we experience Him in our lives.
Thus today's psalm calls God "the guardian of Israel". This thought controls the sense of the following verses, so that the word "guard" is repeated several times. The opening verses talk about help: we look for help and realize that help comes from God: God gives us help whenever we need it. The title "guardian" implies more: even before we ask, God is present, guarding and protecting us.
This Psalm is a pilgrimage psalm, reflecting the difficult journey through mountains that the pilgrim had to experience on his way to Jerusalem. Since Vatican II, we have learned to speak of the Church as a "pilgrim Church" on a journey through this world to our heavenly Jerusalem. The pilgrim author of this psalm going through the mountain to the earthly Jerusalem, has provided us with a very simple and beautiful prayer to accompany us on our own pilgrimage.
Lord, be our guide and guardian on the pilgrimage of life.