This section is taken from John T. Seamands book, "Tell It Well: Communicating the Gospel Across Cultures."
Milk can be delivered in a variety of containers. It my be in a tin can, a glass bottle, cardboard carton, or a plastic bottle. The type of container is not so important, as long as the milk is pure milk--not soured or watered down. The only condition in which the container might become an important item is when the buyer has a strong personal preference for a particular type of container. He may refuse to buy milk in a tin can, but be most willing to purchase it in a cardboard carton. In the same way, the Christian messenger has no right to water down the content of the gospel--it must be the truth--but he certainly must present it in such a form that will be meaningful to the listener.