The NET Bible on John 10:30 claims "the phrase ἕν ἐσμεν is a significant assertion with trinitarian implications, i.e., the "essential unity (unity of essence)" of Father and Son. Yet, later in John 17:21-23 Jesus prays to the Father that Christians "may be one just as we are one"!
The point is Jesus was not some neo-Platonist, let alone nascent Trinitarian! So, "There’s no break between the OT and New. The monotheistic tradition is continued. Jesus was a Jew, trained by Jewish parents in the OT scriptures. His teaching was Jewish to the core; a new gospel indeed but not a new theology.” (Paine, A Critical History of the Evolution of Trinitarianism, 1900, p. 4) In other words, “Jesus was a first-century Jewish monotheist.” (Wright, Jesus and the Victory of God, p. 652) And this was consistent with the historical fact that "believers in God as a single person (God the Father), were at the beginning of the 3rd century still forming the large majority.” (Encyclopedia Brittanica)
The point is Jesus was not some neo-Platonist, let alone nascent Trinitarian! So, "There’s no break between the OT and New. The monotheistic tradition is continued. Jesus was a Jew, trained by Jewish parents in the OT scriptures. His teaching was Jewish to the core; a new gospel indeed but not a new theology.” (Paine, A Critical History of the Evolution of Trinitarianism, 1900, p. 4) In other words, “Jesus was a first-century Jewish monotheist.” (Wright, Jesus and the Victory of God, p. 652) And this was consistent with the historical fact that "believers in God as a single person (God the Father), were at the beginning of the 3rd century still forming the large majority.” (Encyclopedia Brittanica)