If the works based preachers were right, if God really did require us to clean up our lives, stop certain sins, produce enough fruit, maintain a certain level of holiness, or “prove” our salvation by changed behavior, then everything is meaningless. This is exactly what Solomon discovered in Ecclesiastes. He looked at life under the sun under the system of human effort, human righteousness, and human performance and declared:
Ecclesiastes 1:2
Vanity of vanities, saith the Preacher, vanity of vanities; all is vanity.
He saw the sun rising and setting, generations coming and going, the wind blowing in circles, the rivers running into the sea yet never filling it. Everything repeats. Nothing new. Nothing lasting. Nothing that actually satisfies. Solomon tried it all: wisdom, pleasure, wealth, power, work, morality.
He was the richest, wisest, most moral man who ever lived under the old covenant and he still concluded: All is vanity and vexation of spirit. Under a system of works and law, nothing you do ever really counts. You can be moral today and still fall tomorrow. You can do good works for 40 years and one failure wipes it all out in their system. You can strive, sweat, cry, repent, and “do better” and still never know if you’ve done enough. That is the curse of works-based religion. You examine your life for “evidence of salvation,” but doubt always creeps back in. All is vanity. What would be the point if that system is always against you.