“Oh, the depth of the riches and wisdom and knowledge of God! How unsearchable are his judgments and how inscrutable his ways” (Rom. 11:33, ESV)!
Let us understand the setting of these words. Paul has just finished presenting the plan of redemption. In chapters 1-3, he stated the divine condemnation of the sinfulness of humankind. In chapters 4-8, he outlined the plan of God in justification, sanctification, election, and eternal security of believers. In chapters 9-11, Paul explained the present rejection and future restoration of Israel and the calling of the Gentiles unto salvation.
In view of this wonderful plan of God, Paul then proceeds to praise the depths of the kindness, grace, and wisdom of God.