Contradiction with Ecclesiastes 1:18
This verse suggests that increased knowledge leads to more grief, which contradicts the comfort and assurance in John 14:1 to not be troubled.
Ecclesiastes 1:18: For in much wisdom [is] much grief: and he that increaseth knowledge increaseth sorrow.
Contradiction with Matthew 5:4
This verse blesses those who mourn, suggesting a recognition or acceptance of being troubled, contrary to John 14:1's admonition not to let one's heart be troubled.
Matthew 5:4: Blessed [are] they that mourn: for they shall be comforted.
Contradiction with Job 14:1
This verse acknowledges that life is full of trouble, which can be seen as contradictory to the reassurance provided in John 14:1.
Job 14:1: Man [that is] born of a woman [is] of few days, and full of trouble. [few...: Heb. short of days]