2 Peter 2:6

2:6 and if he turned to ashes the cities of Sodom and Gomorrah when he condemned them to destruction, having appointed them to serve as an example to future generations of the ungodly,

Jude 1:7

1:7 So also Sodom and Gomorrah and the neighboring towns, since they indulged in sexual immorality and pursued unnatural desire in a way similar to these angels, are now displayed as an example by suffering the punishment of eternal fire.