2 Peter 2:6

He condemned the cities of Sodom and Gomorrah and reduced them to ashes, holding them up as a warning to the godless of what was in store for them;

1 Corinthians 10:6-10

Now these things happened as warnings to us, to teach us not to long for evil things as our forefathers longed.

Jude 1:7

Like Sodom and Gomorrah and the towns near them, which gave themselves up to fornication, and fell into unnatural vice, these angels now stand out as a warning, undergoing, as they are, the punishment of aeonian fire.

Treasury of Scripture Knowledge

Summary

And the earth opened her mouth, and swallowed them up together with Korah, when that company died, what time the fire devoured two hundred and fifty men: and they became a sign.

Bible References

They became a sign

1 Corinthians 10:6
Now these things happened as warnings to us, to teach us not to long for evil things as our forefathers longed.
2 Peter 2:6
He condemned the cities of Sodom and Gomorrah and reduced them to ashes, holding them up as a warning to the godless of what was in store for them;
Jude 1:7
Like Sodom and Gomorrah and the towns near them, which gave themselves up to fornication, and fell into unnatural vice, these angels now stand out as a warning, undergoing, as they are, the punishment of aeonian fire.