Well jaybird there are a number of places but my personal favorite is John 10:30. And when you say "one" in what respect are you asking how they are one? The one God, one person, one in purpose, or how are they one? But before I address this issue why have you not address what I posted to you regading another question you ask. Please read the following:
"That's right jaybird, He did teach that but obviously you don't know why? So can you please tell me how you reconcile what Jesus said at John 4:23 to what the Apostle Thomas said at John 20:28 where he declared to Jesus Christ that He/Jesus was his "Lord and God?" Which btw is the highest form of worship for an orthodox Jew to say to a man only (like you and others believe) that Jesus Christ is his "Lord and God."
So why would Thomas say that and moreover why does Jesus Christ not correct Thomas and tell him is wrong? I mean afterall did not Jesus Himself say at Luke 4:8, "It is written, You shall worship the Lord your God and serve Him only." How do you explain or reconcile all of this jaybird? I would really like to know?
" I'm still waiting for your answer?
Now, getting back to this one business. When Trinitarians say that the three pesons of the Trinity are one they usually mean "one in nature." There is plenty of proof that they are one in purpose but at John 10:30 Jesus is telling the Jews that He and His Father, we are one."
In this context Jesus had just said that the sheep are equally safe in His hand and in His Father's hand. The power of the Son is equal to that of the Father. Even more importantly Jesus is explaining out of those words literally "I and the Father, we are one." Jesus distinguishes the "I" from the "Father" and uses the plural verb "are" denoting "we are." The word "one" in this instance is "hen." It is a neuter number to indicate, EQUALITY OF ESSENCE, ATTRIBUTES, DESIGN, WILL AND WORK. In short, one asserts their unity of essence or nature as identical.
This is backed by how the Jews react to what Jesus had said. John 10:31, "The Jews took up stones again to stone Him." Why jaybird? Vs33 gives the answer, "The Jews answered Him, "For a good work we do not stone You, but for BLASPHEMY; and because You, being a man, MAKE YOURSELF OUT GOD."
At this point don't let ANYONE tell you or come up with the excuse that I have heard hundreds of times that the Jews did not UNDERSTAND what Jesus was saying in may instances by accusing Him of blasphemy. The Jews were "NOT" taking Jesus out of context and they knew exactly what Jesus was claiming. The reason I know this for a fact is because at John 10:36 Jesus directly addresses the issue of Him being accused of blasphemy which means that at John 10:30 Jesus is not simply talking about He and His Father being one in unity or purpose in the same vain as John 17:21.
So jaybird, instead of asking only "why" questions all the time how about addressing some of the answers that have been given you?
IN GOD THE SON,
bluto