In this verse Phillips‘ translation conveys very well the force of the Greek preposition en as meaning “on the basis of.” It says, “God’s purpose was that your faith should not rest upon man’s cleverness but upon the power of God.”

The words your faith may be rephrased as “your trusting in Christ.”

Might not rest in (Good News Bible “does not rest on”) can be stated as “is not the result of” or “is not caused by.” One may rephrase this verse in the following way: “So, it is not human wisdom which caused you to trust in Christ, but the power of God.”

Quoted with permission from Ellingworth, Paul and Hatton, Howard A. A Handbook on Paul’s First Letter to the Corinthians, 2nd edition. (UBS Handbook Series). New York: UBS, 1985/1994. For this and other handbooks for translators see here .