Deuteronomy 32:22
For a fire is kindled in mine anger, and shall burn unto the lowest hell, and shall consume the earth with her increase, and set on fire the foundations of the mountains. For a fire is kindled in mine anger, and shall burn unto the lowest hell, and shall consume the earth with her increase, and set on fire the foundations of the mountains.
The verse belongs to the song in Deuteronomy 32:1-43 that God commanded Moses to frame from His dealings with ancient Israel, so the history of His power, care, goodness, mercy and deliverance would be kept in remembrance and not be forgotten. The song was to be taught by parents to children, with memorials gathered and kept in sight, so that when children inquired the whole story of His providential dealings and marked goodness and mercy in His care and deliverance could be repeated and kept in mind, giving reason for joy, gladness, praise and thanksgiving, and providing the pattern for often recounting His goodness and wonderful works in this generation.
The verse warns that Israel's forsaking, forgetting and rejecting God and worshiping other and strange gods through idolatry and unfaithfulness provoked His anger and kindled the fire. The kindled fire is a picture of His swift, consuming judgment against persistent rebellion, revealing His abhorrence of sin: it burns to the lowest hell, consumes the earth and land with its increase and produce, and sets on fire the foundations of the mountains.
The warning showed Josiah the danger Judah faced because of its continued apostasy. The song that contains the verse recounts His past dealings with Israel and also prophesies future events, including the final victory of the faithful when Christ comes again in power and glory. The verse applies to people who turn from the God of Israel and trust evil spirits instead: such reliance cannot secure His help or blessing.