And, he does make it clear that He and God the Father are One. But, even apart from that, he constantly extolled the God of the Old Testament. He had no issue with the law handed down to Moses.
And, he makes clear his endorsement of Paul's teachings (Book of Acts, for example).
It is in purpose not reality. For example, my father is doctor and I am a doctor too, so I can say me and my father are one but that doesn't mean I and my father are ONE. It is in purpose. Please read verses before it to become more clear. I'sa prophet was messenger and came to teach good things and about belief of one god.

~~MZ~~