Contradiction with Psalms 22:1
While Psalms 4:6 speaks of seeking the face of God and experiencing His light, Psalms 22:1 describes a feeling of abandonment by God.
Psalms 22:1: [To the chief Musician upon Aijeleth Shahar, A Psalm of David.] My God, my God, why hast thou forsaken me? [why art thou so] far from helping me, [and from] the words of my roaring? [Aijeleth...: or, the hind of the morning] [helping...: Heb. my salvation]
Contradiction with Ecclesiastes 1:2
Psalms 4:6 asks who will show good, seeking divine favor, whereas Ecclesiastes 1:2 declares everything as vanity, suggesting a sense of meaninglessness.
Ecclesiastes 1:2: Vanity of vanities, saith the Preacher, vanity of vanities; all [is] vanity.
Contradiction with Jeremiah 8:15
Psalms 4:6 expresses hope for God's goodness, but Jeremiah 8:15 reflects despair, expecting good but instead finding trouble.
Jeremiah 8:15: We looked for peace, but no good [came; and] for a time of health, and behold trouble!
Contradiction with Lamentations 3:17
While Psalms 4:6 seeks the joy and peace of God's light, Lamentations 3:17 speaks of losing peace and forgetting prosperity.
Lamentations 3:17: And thou hast removed my soul far off from peace: I forgat prosperity. [prosperity: Heb. good]
Contradiction with Job 30:26
Psalms 4:6 is a prayer for God's blessing and light, yet Job 30:26 expresses seeking good and encountering evil, expecting light but finding darkness.
Job 30:26: When I looked for good, then evil came [unto me]: and when I waited for light, there came darkness.