Here is a letter from Adoniram Judson to young missionary candidates. It caught my eye, ’cause I would like to go into missions… here are a couple of his points:
Fourthly. Take care that the attention you receive at home, the unfavorable circumstances in which you will be placed on board ship, and the unmissionary examples you may possibly meet with at some missionary stations, do not transform you from living missionaries to mere skeletons before you reach the place of your destination. It may be profitable to bear in mind, that a large proportion of those who come out on a mission to the East die within five years after leaving their native land. Walk softly, therefore; death is narrowly watching your steps.
Fifthly. Beware of the reaction which will take place soon after reaching your field of labor. There you will perhaps find native Christians, of whose merits or demerits you can not judge correctly without some familiar acquaintance with their language. Some appearances will combine to disappoint and disgust you. You will meet with disappointments and discouragements, of which it is impossible to form a correct idea from written accounts, and which will lead you, at first, almost to regret that you have embarked in the cause. You will see men and women whom you have been accustomed to view through a telescope some thousands of miles long. Such an instrument is apt to magnify. Beware, therefore, of the reaction you will experience from a combination of all these causes, lest you become disheartened at commencing your work, or take up a prejudice against some persons and places, which will embitter all your future lives.
Click here for the full letter from A. Judson.