Paul wrote to the believers at Corinth, “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 immersed into Moses in the cloud and in the sea” (1 Corinthians 10:1-2).
In Paul’s day, one who wanted to become a disciple of Yeshua had to go through a ritual immersion. This rule applied to both Jews and Gentiles. Prior to the immersion, the new disciple confessed and renounced his sins in keeping with the tradition of John’s immersion. Then he descended into a gathering of living water “for the name of Yeshua.” The immersion brought ceremonial cleansing from Levitical impurity, and it symbolized spiritual cleansing, death, and resurrection.
Judaism teaches that one who immerses in a mikvah (immersion pool) symbolically dies as he descends into the water and is reborn as he leaves the water. The apostles applied the death and rebirth imagery of the immersion ritual:
Or do you not know that all of us who have been baptized into Messiah Yeshua have been baptized into His death? Therefore we have been buried with Him through baptism into death … if we have become united with Him in the likeness of His death, certainly we shall also be in the likeness of His resurrection. (Romans 6:3-5)
For the apostles, immersion into the name of Messiah represented the transition from death to life, from the kingdom of darkness to the kingdom of light. By way of analogy, Paul saw the same imagery at work in the crossing of the sea. The children of Israel left Egypt, Pharaoh, and slavery behind as they descended into the water, and they arose on the other side as free men—a people ransomed by God.
Paul warned the Corinthians not to think too highly of themselves. Paul warned them that the generation that perished in the wilderness had similar credentials to their own. They had all been “immersed into Moses in the cloud and the sea,” yet they did not enter the Promised Land (which is compared to the Messianic Era).
Paul was not the only Torah teacher to compare the crossing of the Red Sea to the water of the mikvah. In the Midrash Rabbah, the nation of Israel passes through the Red Sea to purify themselves in preparation for their journey to Mount Sinai:
The crossing of the sea can be compared to a woman who, having completed the days of uncleanness, purified herself and came to her husband. When he saw her he asked, “Who can testify that you are clean?” She replied, “Behold, my maid can testify that I have purified myself by immersion in the mikvah.” (Exodus Rabbah 23:12)