We should believe what Jesus said, ALL of what he said. The Bible interprets itself, and Jesus' words interpret his other words.
An example of the Bible interpreting itself: Trinitarians point to John 1:1 as proof that Jesus is God. But, the Greek manuscript says that "the word was with the god, and god was the word.". There are no capital letters in ancient unical Greek, so the fact that the first word "god" has a "the" in front of it, but the second word "god" does not, shows that one refers to identity, while the other refers to description. The word "god", or other words, in the predicate with no "the" in front of it is used many times to describe people, like Acts 28:6.
Jehovah's witnesses are not the only people who recognize this distinction. Other translations say that the word is divine. Moffatt and American Translation are two of these.
However, John 1:18 states that no man has seen (the) God at any time. Men have seen Jesus - even history has confirmed that. So The God who no man has seen is not Jesus.
Jesus stated "I and the Father are one." John 10:30 He explained what he meant in his prayer to his Father, when he prayed that those who put faith in him "may be one just as we are one." John 17:22 This clearly shows that the relationship between Jesus and his Father is not trinitarian, or even dualitarian, but harmony of thinking and actions, which he prayed would be the case with all of those who put faith in him. Jesus' words.
There are many in the Bible who are called god or God - human judges, angels, pagan gods, Satan, and Jesus Christ. "God" means "mighty one", and this title, god, applies to all of them, either good or bad. So to distinguish the true God from Jesus or anyone else, you have to look for the personal name. The ancient inspired manuscripts contained God's personal name almost 7000 times. Early copies of the Greek Septuagint version, which most Bible historians agree was used by the Christian scripture writers, also contained the name of God in Hebrew.
Jesus said "hallowed be thy name." He also said, "I made your name known to those whom you have given to me" and "I have made your name known and will continue to make your name know, in order that the love that you have for me might be in them and I in union with them." Matthew 6:9; John 17:6,26 Jesus' words.
But when the trinity became popular, and eventually even became required by Emperor Theodosius in the Roman Empire in the 4th century, the name of God was gradually changed to Lord and God. The true God's words were changed by imperfect men in the name of an unscriptural doctrine. So the distinction between the one Almighty God and his firstborn, only begotten Son were blurred.
Jesus said his Father is greater than he is. John 14:28 Jesus said that his Father knew things that neither he nor the angels knew. Matthew 24:36 Jesus called his Father the only true God John 17:3 Even in heavenly glory, Jesus' Father is still his God. Revelation 3:2,12 Again, Jesus' words.
Not only John 1:1, but 1 Timothy 3:16 (where "who" was changed to "God"- apparently a scribal typographical error) and 1 John 5:7 (which inserted a blatantly trinitarian phrase long after John's death) were direct spurious additions to the God-inspired 1st century Bible writers' words.
So you tell me, who is telling the truth?