Contradiction with Proverbs 26:27
Proverbs 26:27 implies that those who dig a pit will fall into it, whereas Ecclesiastes 10:9 does not ascribe personal consequences to the laborer himself.
Proverbs 26:27: Whoso diggeth a pit shall fall therein: and he that rolleth a stone, it will return upon him.
Contradiction with Galatians 6:7
Galatians 6:7 states that a man reaps what he sows, suggesting a direct consequence of one's actions, while Ecclesiastes 10:9 describes an external event happening to the laborer without indicating a cause-and-effect relationship based on the laborer’s intent.
Galatians 6:7: Be not deceived; God is not mocked: for whatsoever a man soweth, that shall he also reap.