How do we know that life is ultimately vain?

The preacher in Ecclesiastes emphasizes the theme of vanity by observing that all human pursuits and endeavors lack lasting significance. In Ecclesiastes 1:14, he states, 'I have seen all the works that are done under the sun; and behold, all is vanity and vexation of spirit.' This perspective reflects the Reformed understanding that apart from God and the eternal perspective, all earthly efforts are ultimately futile. The cyclical nature of life, where achievements fade and are forgotten, highlights the transient nature of human existence without a focus on divine grace and eternal truth.