We are used to thinking that the meaning of a text is in the words. But this meaning is controlled by the context that each word is in. That is, the meaning of the individual words is controlled by the levels above it, including the phrases, sentences, and paragraphs. For example, a single word like "give" may have the following possible meanings, depending on the context (the higher levels):
The translator must determine what each word means in each context, and then reproduce that same meaning in the translated text. That means that words cannot be translated individually, but only with the meaning that they have when they are combined together with the other words in the phrases, sentences, paragraphs, and chapters in which they form a part. That is why the translator must read the whole paragraph, chapter, or book that he is translating before starting to translate it. By reading the larger levels, he will understand how each of the lower levels fits into the whole, and will translate each part so that it communicates the meaning in a way that makes the most sense with the higher levels.