The work of the Sufi is therefore to investigate the truth about all things or persons whom he likes or dislikes. By a keen observation of life he gets to that barrier and understands what it is that makes him disliked or makes him dislike others. All fear, doubt, suspicion, misunderstanding, bitterness, or spite becomes cleared as soon as one touches that barrier which keeps souls apart. It is true that one need not force one's nature. It is not necessary to dislike what one likes or to take a liking to something that by nature one dislikes; only one must know why one likes if one likes a certain thing, and the reason why one dislikes if one takes a dislike to a certain thing.