Note 9 at 1Co 1:25: God is never foolish or weak, yet the foolish often perceive Him that way.

Paul had just made reference to how the wisdom of man viewed the crucifixion of Christ as foolishness (1Co 1:23). So, in context, Paul was saying that Christ and His method of salvation through faith in His grace (see note 1 at 1Co 1:18), are wiser and better than any plan of salvation that man could ever design.