1 Cor 10:1-2
For I do not want you to be unaware, brethren, that our fathers were all under the cloud and all passed through the sea; and all were baptized into Moses in the cloud and in the sea.

Moses was God's representative to the people and symbolized of the Law of God. This passage is saying that these two events, being covered by God in the cloud and passing through the Red Sea, were like being baptized into God's covenant. Moses was the symbol of the Old Covenant, so they were said to have been "baptized into Moses". Baptism pictures dying to an old life and being raised in a new life.

Certainly passing through the Red Sea spoke of that very well. Israel "died" to the old life of slavery in Egypt, and came out on the other side to a new life of serving God. In the same way, Christians die to the old life of slavery to sin and are born again in a new life of fellowship with God.