William Burkitt on Romans 11:33

Here the apostle concludes the chapter with an awful admiration at the depth of the abundant grace and goodness of God in bearing with the infidelity of the Jews, and the obstinacy of the Gentiles; as also of his unsearchable wisdom in making first the rejection of the Jews a mean of calling the Gentiles, and then working upon the obstinate Jews by his mercy unto the Gentiles.

By judgments here, some understand the degrees and determinations of God's will; by ways, the administration of his providence, in order to the execution of those decrees: both which are secret, unsearchable, and unfathomable. There are mysteries of providence, as well as mysteries of faith, and both of them transcend our human understanding.