According to Paul, we should not do wrong things like some people did a long time ago, which caused many of them to die quickly. He is warning us to make good choices so we don't get into trouble.
1 Corinthians 10:8: Neither let us commit fornication, as some of them committed, and fell in one day three and twenty thousand.
Numbers 25:9 states that 24,000 died in the plague, while 1 Corinthians 10:8 claims 23,000 fell in one day, indicating a discrepancy in the death toll count.
Numbers 25:9: And those that died in the plague were twenty and four thousand.