1 Corinthians 10:5

Still further did He also make it manifest, that we ought, after our calling, to be also adorned with works of righteousness, so that the Spirit of God may rest upon us; for this is the wedding garment, of which also the apostle speaks, "Not for that we would be unclothed, but clothed upon, that mortality might be swallowed up by immortality." But those who have indeed been called to God's supper, yet have not received the Holy Spirit, because of their wicked conduct "shall be," He declares, "cast into outer darkness."

Paul wants to remind us that we are not saved merely because we happen to have been the recipients of God's free grace. We have to demonstrate that we are willing recipients of that free gift. The children of Israel received it, but they proved to be unworthy of it, and so they were not saved.

"That our fathers," saith he, "were all under the cloud, and all passed through the sea; and were all baptized unto Moses in the cloud and in the sea; and did all eat the same spiritual meat; and did all drink the same spiritual drink; for they drank of a spiritual Rock that followed them: and the Rock was Christ. Howbeit with most of them God was not well pleased." And wherefore saith he these things? To point out that as they were nothing profited by the enjoyment of so great a gift, so neither these by obtaining Baptism and partaking of spiritual Mysteries, except they go on and show forth a life worthy of this grace. Wherefore also he introduces the types both of Baptism and of the Mysteries. But what is, "They were baptized into Moses?" Like as we, on our belief in Christ and His resurrection, are baptized, as being destined in our own persons to partake in the same mysteries; for, "we are baptized," saith he, "for the dead," i.e., for our own bodies; even so they putting confidence in Moses, i.e., having seen him cross first, ventured also themselves into the waters. But because he wishes to bring the Type near the Truth; he speaks it not thus, but uses the terms of the Truth even concerning the Type. Further: this was a symbol of the Font, and that which follows, of the Holy Table. For as thou eatest the Lord's Body, so they the manna: and as thou drinkest the Blood, so they water from a rock. For though they were things of sense which were produced, yet were they spiritually exhibited, not according to the order of nature, but according to the gracious intention of the gift, and together with the body nourished also the soul, leading it unto faith. […]

"For they were overthrown," saith he, "in the wilderness." Declaring by this word both the sweeping destruction, and the punishments and the vengeance inflicted by God, and that they did not so much as attain to the rewards proposed to them. Neither were they in the land of promise when He did these things unto them, but without and afar somewhere, and wide of that country; He thus visiting them with a double vengeance, both by not permitting them to see the land, and this too though promised unto them, and also by actual severe punishment. And what are these things to us? say you. To thee surely they belong. Wherefore also he adds, "Now these things were figures of us."

Although God showed them many signs of love and deemed them worthy of very many blessings, nevertheless in the majority of them He did not find what was pleasing to Himself, "was not well pleased." For not all were rejected, but many. By the words …