And the LORD went before them by day in a pillar of a cloud, to lead them the way; and by night in a pillar of fire, to give them light; to go by day and night: He took not away the pillar of the cloud by day, nor the pillar of fire by night, from before the people. (Exodus 13:21-22)
We often think of the Holy Spirit, the Third Person of the Trinity, in New Testament terms. However, we have an abundance of evidence of His work in the Old Testament beginning with the first chapter of Genesis where He energizes Creation.