That covers a lot. In fact, knowledge about our world and the people who live in it has increased so greatly in recent years that even the combined knowledge of a thousand different experts could not encompass all there is to know about the world.
Christian missionaries, more than anyone else, should want to know all they can about the world. This is because they have been impressed with the love that God has for all people and for the earth that God has made to be their home.
You have a better chance to know this world than anyone who has ever lived before you. Libraries, universities, magazines and countless other sources are stuffed with knowledge about everything under the sun. Radio, TV, [internet] and movies take you at a flip of a switch to the latest findings anywhere. And in a relatively few hours you can go yourself to the most remote places and see and hear what a few years ago were hidden secrets about peoples and nations, about languages and cultures, about plants and animals, about weather, jungles, diseases and countless other things.
Be always a learner. Be everlastingly curious and inquisitive. Ask questions. Open up your eyes and ears and mind to all you can discover about this complex, wonderful, fearful world. This world is what Jesus called our “field.” As good farmers carefully tend their fields, so good missionaries will study and cultivate their world.