A.B. Simpson emphasizes the duality of human insufficiency and Christ's all-sufficiency, asserting that recognizing our helplessness is essential for spiritual growth. He explains that the Old Testament highlights human failure, while the New Testament reveals Christ's ability to meet all our needs. Simpson encourages believers to renounce their own perceived perfection and embrace Christ's righteousness, which leads to a deeper understanding of grace. He warns that acknowledging our insufficiency must be coupled with a firm faith that claims all that Christ offers. The sermon concludes with a call to humility and a full acceptance of God's greatness and grace.

Not sufficient-all sufficient. These two expressions are the complement of each other. Together they are the key to an effective Christian life. The discovery and full conviction of our utter helplessness is the constant condition for spiritual supply. The aim of the Old Testament, therefore, is ever to show man's failure; that of the New, to reveal Christ's sufficiency. He has all things for us, but we cannot receive them until we admit that we have nothing. The very essence, therefore, of Christian perfection is the constant renunciation of our own perfection and the continual acceptance of Christ's righteousness. And as we receive deeper views of our nothingness and evil, it prompts us to claim more of His rich grace. But it is possible fully to realize our insufficiency and yet not take a firm hold of His "all things." This, too, must be done with a faith that will not accept less than all. The prophet was angry because the king of Israel struck the arrows upon the ground only three times. Had he done so five or six times, he could have had all (see 2 Kings 13:14-19). So let us meet God's full requirement. In humility let us receive His greatness and grace.