But if anyone [i.e., a preacher or soul winner] builds on this foundation with gold, silver, expensive building stones, wood, grass, or straw,

Using the unearned favor shown to me by God [Note: Paul here probably refers to his apostleship and its attending spiritual gifts], as an expert building contractor, I laid the foundation [i.e., in starting the Corinthian church], and someone else is building on it [i.e., Apollos. See verse 6].

For no one can lay [any] other foundation than the one which [God] has [already] laid, which is Jesus Christ.