Yesterday in small group bible study we were reading over Genesis 17:19.

In the NIV it begins, "Then God said, 'Yes, but your wife Sarah will bear you a son, and your will call him Isaac."
In the NKJV it reads, "Then God said: 'No, Sarah your wife shall bear you a son, and you shall call his name Isaac;"

We were all pretty amazed at how different the translations were. It confused us about how to interpret the previous verse, because it depended on whether the translation was yes or no.