"Avoid Independent Thinking... How is such independent thinking manifested? A common way is by questioning the counsel that is provided by God's visible organization." - The Watchtower January 15, 1983 p. 22
The incident of the Ethiopian eunuch is often used by the Watchtower to show that we need the help of an organization to understand the Bible.
However, reading the entire book of Acts, helps us to see that it does not say that at all.
The Ethiopian eunuch was not a Christian, but Philip was used by the Holy Spirit to lead him to Christ. The passage goes on to say: "Jehovah's spirit quickly led Philip away, and the eunuch did not see him anymore." (NWT, emphsis mine.) God led Philip to the eunuch, Philip gave the man the Gospel, baptized him, then God led him away.
Does this sound as though Jehovah God thought it necessary for the eunuch to remain in contact with a central organization? He was probably one of the first Christians in Ethiopia. If we follow the Watchtower's interpretation, the eunuch must have gone into spiritual darkness shortly thereafter, without God's organization to guide him. But, no, he did not go into darkness, for he had the Holy Spirit as his guide, comforter, and teacher. (John 14:16, 17, 26.) God often uses Christians to explain the message of salvation to unbelievers. Acts chapter 8 is not telling us that Christians must submit to a human teacher. Notice what the apostle John said on this subject later: "And as for you, the anointing that you received from him remains in you, and you do not need anyone to be teaching you; but, as the anointing from him is teaching you about all things, and is true and is no lie, and just as it has taught you, remain in union with him." (1 John 2:27, NWT, emphasis mine.)
While the Watchtower organization does not want its members to questions their doctrines, Jehovah says differently. We are all responsible for our own salvation.