Contradiction with Ecclesiastes 3:2
This verse mentions "a time to die," whereas Psalms 21:4 speaks of being given life for an extended period, indicating longevity instead of life's finite nature.
Ecclesiastes 3:2: A time to be born, and a time to die; a time to plant, and a time to pluck up [that which is] planted; [to be...: Heb. to bear]
Contradiction with Hebrews 9:27
This verse states that it is appointed for humans to die once, contradictory to the promise of eternal life or extended years depicted in Psalms 21:4.
Hebrews 9:27: And as it is appointed unto men once to die, but after this the judgment:
Contradiction with 1 Peter 1:24
This verse compares all flesh to grass that withers, which contradicts the idea of enduring life as granted in Psalms 21:4.
1 Peter 1:24: For all flesh [is] as grass, and all the glory of man as the flower of grass. The grass withereth, and the flower thereof falleth away: [For: or, For that]