How do we know that humans are weak and sinful according to the Bible?

The Scriptures, especially in the Old Testament wisdom literature and the Psalms, depict man as weak, vain, and sinful. In Job 15:14, it questions, 'What is man that he should be clean?' indicating the inherent sinfulness found in humanity. Additionally, we have Ecclesiastes 12:7 which speaks of the dust returning to the ground, signifying man's mortality. Furthermore, Romans 3:23 states, 'For all have sinned and fall short of the glory of God,' reinforcing the universal condition of sinfulness and the need for grace through Jesus Christ's atoning work. This reflects the historic Reformed understanding of total depravity, where all aspects of human nature are tainted by sin.