Contradiction with Philippians 1:21
While Ecclesiastes 6:6 implies futility in long life without fulfillment, Philippians 1:21 emphasizes the meaningfulness of life in Christ.
Philippians 1:21: For to me to live [is] Christ, and to die [is] gain.
Contradiction with Psalm 23:1
Ecclesiastes 6:6 suggests life's endeavors can be unfulfilling, while Psalm 23:1 conveys the Lord as the shepherd who provides and fulfills all needs.
Psalm 23:1: [A Psalm of David.] The LORD [is] my shepherd; I shall not want.
Contradiction with John 10:10
Ecclesiastes 6:6 points to ultimate futility, while John 10:10 speaks of fullness and abundance of life through Jesus.
John 10:10: The thief cometh not, but for to steal, and to kill, and to destroy: I am come that they might have life, and that they might have [it] more abundantly.
Contradiction with Romans 8:28
Ecclesiastes 6:6 questions the value of long life, unlike Romans 8:28 which assures that all things work together for good.
Romans 8:28: And we know that all things work together for good to them that love God, to them who are the called according to [his] purpose.
Contradiction with Matthew 5:12
Ecclesiastes 6:6 suggests no gain beyond life, whereas Matthew 5:12 speaks about rewards in heaven.
Matthew 5:12: Rejoice, and be exceeding glad: for great [is] your reward in heaven: for so persecuted they the prophets which were before you.