Originally Posted by Gourmet Greg
Knives are different from other utensils in that you are likely to need the same knife on different cutting jobs during preparation of the same meal. Most likely you will not want to cross-contaminate foods so it only makes sense to wash the knife off (usually just rinsing under hot water), dry it off and put it back in the block where it is once again available for use. Then when you need another knife they're all there in the block, ready to choose the best knife for the job. When you're done cooking dinner you should end up with all the knives used in preparation already cleaned and back stored in the knife block.
I often use more than one knife during prep. Between ingredients, I give the knife a quick rinse and swipe on a kitchen cloth to semi-dry it. But it sits on the counter until it's been washed with soap and water before it gets honed and returned to storage.