Psalm 66 serves as a song or psalm directed to a choir leader. It calls for widespread praise and worship of God for his awesome deeds and power, specifically referencing the miracle of parting the Red Sea and leading his people through trials. The speaker also recounts personal experience of being tested and delivered by God, offering sacrifices and fulfilling vows in gratitude. Finally, the psalm concludes with acknowledgment of God's attentive ear to prayer and unfailing love.