Moreover, brethren, I do not want you to be unaware that all our fathers were under the cloud, all passed through the sea, all were baptized into Moses in the cloud and in the sea.
The apostle Paul used the examples of the ancient Israelites to teach lessons to the Christians of his day—and ours.
When God led the Israelites out of slavery in Egypt, He used several miracles that symbolize the Christian life. He led Israel with a pillar of cloud (which became a pillar of fire at night). He also led them through the midst of the Red Sea with walls of water on either side.
Paul used the cloud and the water of the Red Sea as symbolic of baptism—immersion in water that signals the start of a new life. Christian baptism pictures the washing away of sin, the death and burial of our “old man” and our rising to walk in newness of life.
Read more about this in the article “What Do the Symbols of Baptism Mean?”