It is (implied)by the course of the argument here, that This was the foundation which had been laid at Corinth, and on which the church there had been reared.
And it is affirmed that no other foundation can be laid.
A foundation is that upon which a building is raised; the foundation of a church is the doctrine on which it is established; that is, the doctrines which its members hold those truths which lie at the basis of their hopes, and by embracing which they have been converted to God.