Psalm 84

This is a psalm of joy. Psalms are filled with variations of the human experience. They reflect the thoughts in the heart of the singer during the expressions recorded in the psalm. In this particular psalm, the author focuses on joy and the true source of joy. 
It is easy to see oneself as joyful when everything lines up and desires are met and fulfilled unabated. That is the type of joy that easily comes to mind. It is the type of joy we can gladly share with others. They can participate in the euphoria of those things that gladden our hearts and maybe hope for the same in their own lives. 
In this Psalm, the author is looking at something external and internal to himself. He is not recounting a joy sourced from acquisition of material things. He is looking at the joy that can only come from God. 
He rejoices in the dwelling house of God for he believes that God is there and for that reason he longs for it in a deep way such that his heart and flesh sings for joy to the living God. 
There are people who easily express their happiness with singing. The heart that is content with God is filled with a joy that surpasses human understanding.
The joy in the presence of God does not end with singing out of joy, it goes to express the care that sparrows and swallows find by building their home and nest and lay their young. 
In this joy, the author expresses the truth of having ones strength and trust in the Lord and the Lord in one’s heart, as it is a blessing. This blessing is such that as they go through the valley of weeping, they make it a place of spring while the early rain covers it with pools. This reveals the strength of God blessing on them and his ability to bring blessings to others through them. All these grants them progress as they grow from strength to strength before God.
After expressing the truth of the blessings of trust in God, he goes back to expressing the belief in his heart that a day in the courts of the Lord is better than a thousand elsewhere just as much as he would rather be a doorkeeper in the house of God that dwell in the tents of wickedness. This shows to us the joy and pleasantness of being in God’s presence than elsewhere. That it is profitable and sensible to trust in God. That a heart that trusts in God is one that seeks to be in the presence of God.
He ends the song by expressing another truth about God, that he is a sun and shield who bestows favor honor and that he does not withhold a good thing from those who walk uprightly which speaks of the myriad of ways God bless his people who trust in him as his nature causes him to make good those things he gives to those who walk according to his uprightness. 
This psalm gets me excited. I think of the many ways in which trusting in God has been justified in many ways in my life. It does not mean I got everything I was looking for but rather, I received every good thing he had for me in my valley of Baca. Indeed, Blessed is the one who trusts in you!JoytrustJoy and trust