Contradiction with Proverbs 19:21
Isaiah 39:5 predicts a certain event, while this verse teaches that the LORD's counsel is what ultimately prevails.
Proverbs 19:21: [There are] many devices in a man's heart; nevertheless the counsel of the LORD, that shall stand.
Contradiction with Jonah 3:10
Isaiah 39:5 suggests a forthcoming judgment by God, whereas this verse shows God's willingness to change his mind based on repentance.
Jonah 3:10: And God saw their works, that they turned from their evil way; and God repented of the evil, that he had said that he would do unto them; and he did [it] not.
Contradiction with Exodus 32:14
In contrast to the impending judgment in Isaiah 39:5, this verse describes how God changed his intended action after Moses' intercession.
Exodus 32:14: And the LORD repented of the evil which he thought to do unto his people.
Contradiction with Habakkuk 2:3
Isaiah 39:5 suggests an imminent prophecy, but this verse emphasizes that the fulfillment of visions and prophecies can be delayed according to God's timing.
Habakkuk 2:3: For the vision [is] yet for an appointed time, but at the end it shall speak, and not lie: though it tarry, wait for it; because it will surely come, it will not tarry.
Contradiction with James 4:13-15
Isaiah 39:5 seems certain about future events, but this passage advises against making presumptive statements about the future without acknowledging God's will.
James 4:13-15: Go to now, ye that say, To day or to morrow we will go into such a city, and continue there a year, and buy and sell, and get gain: