In Psalms Book 3 there are five outstanding psalms.
Psalm 73 unveils God as our unique portion. Here the psalmist declares, "Whom do I have in heaven but You?/And besides You there is nothing I desire on earth" (v. 25).
Psalm 80 unveils Christ as the One in the place of preeminence. In verse 17 the psalmist prays, saying, "Let Your hand be upon the man of Your right hand,/Upon the son of man whom You have strengthened for Yourself." This psalm reveals that in the entire universe Christ has the place of preeminence.
Psalm 84 unveils Christ as the house of God with the two altars for the "sparrows" and the "swallows," that is, for the weak ones. We may be weak "sparrows" and "swallows," but we enjoy the incarnated Triune God with the two altars as His two great consummations.
Psalm 87 unveils Zion with Christ loved by God. This signifies the church with Christ and with so many saints loved by God, for Zion will be God's house and also God's city as the kingdom for God to gain the entire earth.