Contradiction with Exodus 34:7
While Psalms 25:6 highlights God's mercy, Exodus 34:7 emphasizes His justice in not clearing the guilty, pointing to potential conflict between mercy and justice.
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 1 Samuel 15:29
Psalms 25:6 speaks to God's mercies and His ability to change outcomes for believers, while 1 Samuel 15:29 states that God does not change His mind, which can seem contradictory regarding divine flexibility in dispensing mercy.
1 Samuel 15:29: And also the Strength of Israel will not lie nor repent: for he [is] not a man, that he should repent. [Strength: or, Eternity, or, Victory]
Contradiction with Isaiah 27:11
Psalms 25:6 refers to God remembering His tender mercies, but Isaiah 27:11 describes a lack of compassion when His creation fails to understand or respond, presenting a seeming inconsistency in the application of mercy.
Isaiah 27:11: When the boughs thereof are withered, they shall be broken off: the women come, [and] set them on fire: for it [is] a people of no understanding: therefore he that made them will not have mercy on them, and he that formed them will shew them no favour.
Contradiction with Hosea 1:6
Hosea 1:6 highlights God withdrawing mercy from Israel, which contradicts the perpetual remembrance of mercy expressed in Psalms 25:6.
Hosea 1:6: And she conceived again, and bare a daughter. And [God] said unto him, Call her name Loruhamah: for I will no more have mercy upon the house of Israel; but I will utterly take them away. [Loruhamah: that is, Not having obtained mercy] [no...: Heb. not add any more to] [but...: or, that I should altogether pardon them]