By saying that, Corin was referencing Calvinist's belief that nothing happens that was not part of God's plan. Therefore, those different parts of Judaism would have been part of the already written script.
So would be your standing up and admitting, "I am a peanut butter sandwich."
Do you believe there are things that happen that are not part of God's plan. Was Katrina part of "God's plan"? Was it part of "God's plan" that "the older shall serve the younger" in the case of Jacob and Esau? Was your salvation part of "God's plan"?
Can you give us an outline from the Bible as to which events fall into "God's plan" and which do not? Thanks.
"Is it not from the mouth of the Most High That woe and well-being proceed?" (Lam. 3:38)