I have long been puzzled by the usage of 'verb + not'. For example, Kennedy said, "... my fellow Americans, ask not what your country can do for you, ask what you can do for your country." The Bible states, "Give not that which is holy unto the dogs, neither cast ye your pearls before swine, lest they trample them under their feet, and turn again and rend you" (Matthew 7:6 KJV).
I think 'verb + not' equals 'do not verb'. Is that so? Can anyone tell me grammatically? Is 'verb + not' only used orally? Is it a formal expression or not?