The lessons from the Old Testament are numerous. The apostles learned from Jesus, and the Holy Spirit revealed multiple truths within the historical accounts of the Old Testament. Apostle Paul learned the parallels between Israel that was led out of Egypt and slavery to Mount Sinai, our forefathers, and the new church. Paul conveyed this truth to the Corinthian congregation as a warning.
A cloud led the Israelites in the desert. They were under God’s leadership and guidance. (Exodus 13:21-22; Numbers 9:15-23; 14:14, Deuteronomy 1:33; Psalm 78:14) The cloud led them through the Red Sea on the way to Mount Sinai. (Exodus 14:22, 29) These parallel the Christian baptisms of the Holy Spirit and water, both of God’s leading. (John 3:5; Acts 22:16)
Manna is paralleled to the bread that Jesus said represents his body (Exodus 16:31; John 6:30-35, 6:49-51, 58; Luke 22:19). Jesus told the Jews after he fed the five thousand, “Your forefathers ate the manna in the desert, yet they died. But here is the bread that comes down from heaven, which a man may eat and not die. I am the living bread that came down from heaven. If anyone eats of this bread, he will live forever. This bread is my flesh, which I will give for the life of the world.”
Similarly, the water from the rock for Israel parallels the wine that represents Jesus’ blood poured out for the salvation of many. (Exodus 16:2-36, 17:6; Numbers 20:2-11, 7-13, 21:16) Jesus told us that the blood seals the new covenant. We drink it to remember Jesus. (11:25; Luke 22:20; John 4:14)
The fact is, before the old covenant was sealed at the foot of the mountain, God was not pleased with many Israelites, and they died. They were not part of the old covenant. Now it is the same with us; the apostle was inspired to warn. Should God become displeased with some in the congregation, He too will not allow them to be part of the sealing of the new covenant. More in the next verses and BDBD.

