Contradiction with Exodus 34:7
Exodus 34:7 describes God as a just figure who punishes iniquity, which can be seen as conflicting with Psalms 31:23 that underscores God preserving the faithful.
Exodus 34:7: Keeping mercy for thousands, forgiving iniquity and transgression and sin, and that will by no means clear [the guilty]; visiting the iniquity of the fathers upon the children, and upon the children's children, unto the third and to the fourth [generation].
Contradiction with Isaiah 57:21
Isaiah 57:21 states there is no peace for the wicked, suggesting a different outcome than the love and preservation mentioned in Psalms 31:23.
Isaiah 57:21: [There is] no peace, saith my God, to the wicked.
Contradiction with Ecclesiastes 9:2
Ecclesiastes 9:2 implies that the same event (death) happens to both the righteous and the wicked, contradicting Psalms 31:23's notion of divine preservation for the faithful.
Ecclesiastes 9:2: All [things come] alike to all: [there is] one event to the righteous, and to the wicked; to the good and to the clean, and to the unclean; to him that sacrificeth, and to him that sacrificeth not: as [is] the good, so [is] the sinner; [and] he that sweareth, as [he] that feareth an oath.
Contradiction with Job 21:7
Job 21:7 questions why the wicked live and age in power, contrasting with the idea in Psalms 31:23 that the wicked are dealt with by God.
Job 21:7: Wherefore do the wicked live, become old, yea, are mighty in power?
Contradiction with Matthew 5:45
Matthew 5:45 indicates that God causes the sun to rise on evil and good alike, suggesting equal treatment contrary to the distinction in Psalms 31:23.
Matthew 5:45: That ye may be the children of your Father which is in heaven: for he maketh his sun to rise on the evil and on the good, and sendeth rain on the just and on the unjust.