This explanation was taken from the reasoning book, page 204.
How do Jehovah’s Witnesses arrive at their explanation of the Bible?
A key factor is that the Witnesses really believe that the Bible is God’s Word and that what it contains is there for our instruction. (2 Tim. 3:16, 17; Rom. 15:4; 1 Cor. 10:11) So they do not resort to philosophical arguments to evade its clear statements of truth or to justify the way of life of people who have abandoned its moral standards.
In pointing out the meaning of symbolic language in the Bible, they let the Bible provide its own explanation, instead of giving their theories as to its significance. (1 Cor. 2:13) Indications as to the meaning of symbolic terms are usually found in other parts of the Bible. (As an example, see Revelation 21:1; then, regarding the meaning of “sea,” read Isaiah 57:20. To identify “the Lamb” referred to in Revelation 14:1, see John 1:29 and 1 Peter 1:19.)
As for fulfillment of prophecy, they apply what Jesus said about being alert to events that correspond to what was foretold. (Luke 21:29-31; compare 2 Peter 1:16-19.) Conscientiously they point out those events and draw attention to what the Bible indicates they mean.
Jesus said that he would have on earth a “faithful and discreet slave” (his anointed followers viewed as a group), through which agency he would provide spiritual food to those making up the household of faith. (Matt. 24:45-47) Jehovah’s Witnesses recognize that arrangement. As was true of first-century Christians, they look to the governing body of that “slave” class to resolve difficult questions—not on the basis of human wisdom, but by drawing on their knowledge of God’s Word and his dealings with his servants, and with the help of God’s spirit, for which they earnestly pray.—Acts 15:1-29; 16:4, 5.