Was the baptism unto Moses in 1 Corinthians 10:2 a water baptism?
No. Although people in the Church age often think the word baptized means water, Israel passed through the Red Sea on dry ground and did not get wet. So the baptism unto Moses in the cloud and in the sea was not a water baptism; it did not make them members of the called-out assembly.
Les teaches that Paul is taking his readers back to Exodus and the parting of the Red Sea. In 1 Corinthians 10:1-2, the fathers were under the cloud and all passed through the sea, and they were baptized unto Moses in the cloud and in the sea. Most people in the Church age immediately think of water when they see the word baptized, but Les says that even though the Red Sea was parted, the Israelites did not get wet; they walked through on dry ground. Therefore, this baptism was not a water baptism. He connects it with the called-out assembly, the Ecclesia, the church in the wilderness, yet Israel was not baptized to become members of that Ecclesia. He also points to Acts 7, where Stephen rehearses Israel's history and their forefathers who came out of Egypt under Moses.
And were all baptized unto Moses in the cloud and in the sea;