Contradiction with Ecclesiastes 9:5
Job 19:27 anticipates a personal and conscious afterlife, while Ecclesiastes 9:5 suggests that the dead know nothing.
Ecclesiastes 9:5: For the living know that they shall die: but the dead know not any thing, neither have they any more a reward; for the memory of them is forgotten.
Contradiction with Psalm 6:5
Job 19:27 expresses hope in seeing God after death, whereas Psalm 6:5 implies that in death there is no remembrance or worship of God.
Psalm 6:5: For in death [there is] no remembrance of thee: in the grave who shall give thee thanks?
Contradiction with Isaiah 38:18
Job 19:27 talks about seeing God after death, but Isaiah 38:18 states that the grave cannot praise or hope for God's truth.
Isaiah 38:18: For the grave cannot praise thee, death can [not] celebrate thee: they that go down into the pit cannot hope for thy truth.