How do we know God's decrees are unchangeable?

The assurance that God's decrees are unchangeable comes from understanding His sovereignty. In Revelation, we see that God has ordained all things and has promised that His purposes will prevail. Scriptures like Isaiah 14:24 remind us that the Lord of hosts has sworn, 'Surely, as I have thought, so it shall come to pass; and as I have purposed, so it shall stand.' This reinforces the belief that nothing in heaven or on earth can alter God's divine plan, for He is both the originator and executor of His will.