84:1-2 The dwelling places of the Lord of armies were His temple and its courtyards. This is where God abode in a localized sense during this period of Israel's history. He promised to meet with His people in a special way there mainly through the mediation of the Levitical priests. The average Israelite could not enter the temple proper but could worship God in its courtyards.
84:3-4 The psalmist considered the birds that made their nests in the temple and its courts as specially privileged since they were always near God. The priests also had a great advantage because they lived in the rooms surrounding the temple. They could praise God always because they were at the center of His worship.
"Three times he uses the word Blessed', or Happy': once wistfully (4), once resolutely (5), once in deep contentment (12). These can guide us in exploring the movement of the psalm."150