Why is the word yahweh not written in the NT? Is it because Yahweh refers
to the whole Godhead?

The reason YHWH (I use YHWH rather than yaweh, as it is closer
the the Hebrew original) does not appear in the New Testament is that the
New Testament was written in Greek. YHWH is a Hebrew word for God. The
Greek word for God is Theos, not YHWH. Of course, Jesus spoke in
Aramaic, not Greek in his everyday speech. Apparently, even in speaking
Aramaic, Jesus did not refer to God as YHWH in his everyday communication
with his disciples or the crowds. The most common word Jesus used for God
was presumably the Aramaic word for Father, which is abba. Similarly,
the word Allah does not appear in English versions of the Bible. The
reason is that Allah is an Arabic word for God. When the Bible is
translated into Arabic, the word Allah is used. It would appear that the
issue of what actual word is used for God is not a major issue to God
(despite claims to the contrary by the Jehovah’s Witness group). We do
not say Theos, even though that is the name for God in the New Testament
because for those who speak English, Theos is not a word. God is our word
for the deity.

The fact is that Jesus did not use the word YHWH for his
father. If he ever did, it is not found in the New Testament. Besides
that, the writers of the New Testament did not use the word. Paul,
Peter, James and so forth, writing in Greek, used terms such as the Greek
words for Lord, God, Father and so forth, but not YHWH. It is worth
bearing in mind that the Jews in the time of Jesus did not use the word
YHWH in their speech either. They had a seemingly superstitious idea
about using the word YHWH to the point that when the word appeared in the
Hebrew Bible, they would substitute another word, as they felt it was not
acceptable for a human being to utter aloud the word YHWH.

Is there a theological reason that Jesus, being part of the
“godhead,” did not use the word YHWH? It is possible that there might be
something to that, as Jesus is divinity. You may have a point. Jesus is
God. For Jesus to call the Father YHWH might have been something he would
not have been done. Traditional theology would have YHWH representing the
totality of deity, which would include the son. Having said that, there
is absolutely no evidence that any of the New Testament writers, and as
far as I know, no evidence that any of the early church leaders either,
used the word YHWH to refer God. The New Testament writers would not have
the same potential theological reasons for not referring to God as YHWH.
Therefore, it would be somewhat speculative to say Jesus did not use the
word because of theological reasons related to the godhead.

By the way, the Jehovah’s Witness group makes a very big deal
about the use of the word Jehovah for God. First of all, the word Jehovah
is not used anywhere in the Hebrew or Greek Bible. Historically, it
derives from a German transliteration of YHWH. The Jehovah’s Witnesses
claim that the original New Testament used Jehovah, not God to refer to
the Father. This is an absolutely false claim. There is literally not a
single piece of evidence that any New Testament writer ever used the word
Jehovah, or YHWH. The idea that the the early church leaders would have
removed the word YHWH from the New Testament is absolutely completely
lacking supporting evidence. This idea is the creation of the imagination
of those with a strong pre-conceived notion about what is the proper name
for God.

In summary, it is possible that issues about the godhead might
have been at least a partial reason that Jesus did not refer to his Father
as YHWH. However, it would be difficult to prove that this is why he did
not use this word. More likely, it was simply not a word that even the
Jews amongst whom he lived used in regular speech to refer to God, and
therefore Jesus did not use this word either. Bottom line, the word YHWH
is not in the New Testament because it is not a word used by the New
Testament writers.

John Oakes, PhD