1 Corinthians 5:8

5:8 So then, let us celebrate the festival, not with the old yeast, the yeast of vice and evil, but with the bread without yeast, the bread of sincerity and truth.

1 Corinthians 10:8-9

10:8 And let us not be immoral, as some of them were, and twenty-three thousand died in a single day. 10:9 And let us not put Christ to the test, as some of them did, and were destroyed by snakes.