Isn't it great to know something for sure? On the other hand, isn't it difficult to not know something for sure? Such as not knowing if the surgery removed all of the malignant cells, not knowing if you have enough fuel to make it to the next gas station, or not knowing where your wallet and keys are.

It is very interesting that when John came to the end of his letter, he underscored the things every believer can know with absolute assurance.