Contradiction with Judges 9:23
This verse describes God sending an evil spirit between Abimelech and the people of Shechem, which contradicts the depiction of God's way as perfect in Psalms 18:30.
Judges 9:23: Then God sent an evil spirit between Abimelech and the men of Shechem; and the men of Shechem dealt treacherously with Abimelech:
Contradiction with Isaiah 45:7
This verse states that God creates both peace and evil, which contradicts Psalms 18:30 where God's way is described as flawless.
Isaiah 45:7: I form the light, and create darkness: I make peace, and create evil: I the LORD do all these [things].
Contradiction with Amos 3:6
This verse suggests that when disaster comes to a city, it is caused by the Lord, contrasting with the perfection described in Psalms 18:30.
Amos 3:6: Shall a trumpet be blown in the city, and the people not be afraid? shall there be evil in a city, and the LORD hath not done [it]? [be afraid: or, run together?] [the LORD...: or, shall not the LORD do somewhat?]
Contradiction with 1 Samuel 16:14
This verse talks about an evil spirit from the Lord troubling Saul, which is contrary to the notion of God's perfection in Psalms 18:30.
1 Samuel 16:14: But the Spirit of the LORD departed from Saul, and an evil spirit from the LORD troubled him. [troubled: or, terrified]
Contradiction with Exodus 32:14
This verse talks about the Lord repenting from the evil He thought to do unto His people, which contradicts the perfection stated in Psalms 18:30.
Exodus 32:14: And the LORD repented of the evil which he thought to do unto his people.