The apostle Paul tells the Corinthians that he would not that they should be ignorant. As we deal with holy things, ignorance is dangerous.
Paul wanted them to know that their fathers were all under the cloud, and they all passed through the sea. The Jews in the wilderness are called the fathers of the Gentiles at Corinth. There was a covenantal identity between them — they, together, constituted the people of God. This is how we, who are not descended from Abraham in the ordinary way, can be considered as sons and daughters of Abraham. The thing which unites us is the covenant, and the heart of keeping this covenant is faith. Faith brought the Jews to the banks of the Red Sea. Faith brought them to the shores of their baptism.
But this by itself does not settle the matter. The Corinthians, and many Christians since, have assumed automatic blessings in the presence of God. But it was in the presence of God that Uzzah was struck down, Uzziah was afflicted with leprosy, Nadab and Abihu were consumed, and many Corinthians got sick and died.
Enormous blessings are set before us here. But we do not want you to be ignorant. Blessings are appropriated by faith, and faith is not automatic. Faith was not handed to you at the door. Faith is not under your seat. Faith receives like a child. Faith is not up in heaven so that you might wonder how it might be retrieved. Faith comes by hearing, and hearing by the Word of God. And this is the Word of God. Here is the body of Christ, broken for His people. Here is the cup of the new testament, the blood shed for the remission of sin. Do you believe? Then take, and eat.