St. Augustine believes that human beings cannot find inner peace apart from God because of his belief that God created human nature. In his account, human beings were made to seek God and find peace in God; thus, the search for God is not foreign to us but rather built into our very being. In a famous passage in the Confessions, Augustine states the following:
Great are You, O Lord, and greatly to be praised; great is Your power, and of Your wisdom there is no end. And man, being a part of Your creation, desires to praise You—man, who bears about with him his mortality, the witness of his sin, even the witness that You resist the proud,—yet man, this part of Your creation, desires to praise You. You move us to delight in praising You; for You have made us for Yourself, and our hearts are restless until they rest in You.
The well-known insight that "our hearts are restless until they rest in You" (cor nostrum inquietum est donec requiescat in te) should be understood to suggest that there can be no peace for human beings apart from resting in, and thus trusting, God. Alternative sources of peace and safety (such as weapons, wealth, and so on) are illusions, because they do not correspond to human nature.
This is consistent with Augustine's emphasis on rejecting worldly goods to the extent that they hinder the search for God and focusing on the aim that reflects the source of human creation. However, Augustine acknowledges that some worldly things (such as philosophy and the pursuit of honor) may point us toward higher pursuits, although they are valuable only in light of their approximation of the highest pursuit, which is of and for God.