The first song found in the Bible is the Song of Moses in Exodus 15. It comes at the culmination of God's deliverance of His people through the plagues and the parting of the Red Sea. The people are now free and safe, and their hearts open up in an expression of praise and thanks to the Lord.
Why sing? And why sing this song about God's triumph in throwing horse and rider into the sea (vs. 1)?
Our faith is not strictly philosophical. Our religion is not merely abstract principles. Indeed, we follow a set of beliefs and a way of life, but our relationship with God is also more than that. It is anchored in the real events and times and places of history. The recorded actions of God testify to the truth of our faith and teach us about Him. Our God is known as the One who frees captives, who protects His people, who works great signs and wonders, and - yes - judges evildoers.
The song of Moses and the Israelites is a joyful expression of that faith. For the first time, God's people receive a sense of just Who He is and how He is on their side. They are jubilant at their deliverance. Slavery had crushed their bodies and threatened to sap their souls, but now their spirits are free and their response is to sing our to the Lord.
The song itself is a recapitulation of all that the people have just experienced. It recounts the destruction of the Pharaoh's army and chariots in the Red Sea (vs. 4). It is a vocalization of praise as well (vs. 11), and a prophecy that looks ahead to the effect of this deliverance when the people enter the Promised Land (vs. 15). They know they need have no fear of the natives, for their God is a mighty God who is sure to prepare the way!