Contradiction with Psalms 62:7
Psalms 62:7 emphasizes that God is the only source of salvation and defense, potentially contradicting the idea of God's protection being specifically linked to the king or anointed leader as in Psalms 89:18.
Psalms 62:7: In God [is] my salvation and my glory: the rock of my strength, [and] my refuge, [is] in God.
Contradiction with Isaiah 31:1
This verse warns against relying on human strength or alliances for help, which may contrast with Psalms 89:18's implication of relying on God's anointed earthly king.
Isaiah 31:1: Woe to them that go down to Egypt for help; and stay on horses, and trust in chariots, because [they are] many; and in horsemen, because they are very strong; but they look not unto the Holy One of Israel, neither seek the LORD!
Contradiction with Hosea 13:10
This verse questions where a king can save or help now, implying a conflict with the notion in Psalms 89:18 of God being the king and benefactor.
Hosea 13:10: I will be thy king: where [is any other] that may save thee in all thy cities? and thy judges of whom thou saidst, Give me a king and princes? [I will...: rather, Where is thy king?]
Contradiction with Jeremiah 17:5
This verse speaks against trusting in man or the flesh, which could contradict relying on an earthly anointed leader as voiced in Psalms 89:18.
Jeremiah 17:5: Thus saith the LORD; Cursed [be] the man that trusteth in man, and maketh flesh his arm, and whose heart departeth from the LORD.