“I and the Father are one.”
Ἐγὼ καὶ ὁ Πατὴρ ἕν ἐσμεν (Egō kia ho Patēr hen esmen), lit., “I and the Father one we are”).
Both historically and currently, Christians have pointed to this passage to show that Jesus indeed claimed equality with God the Father. As with Jesus’ other undeniable claims to be equal with and truly God (Matt. 12:6; John 5:17-18; 8:58-59 et al; Rev. 1:7-8, 17; 2:8; 22:13; etc.), the response of the Jews in verse 33 is an irrefutable confirmation of Jesus’ claim: “For a good work we do not stone You, but for blasphemy; and because You, being a man, make Yourself out to be God.” This passage also provides a clear refutation to the Oneness view, which erroneously asserts that Jesus is the Father (i.e., the same person). Ironically, Oneness advocates actually use it as a so-called proof text. Aside from the fact that throughout chapter 10, Jesus and the Father are clearly differentiated as two persons (vv. 15, 17, 18, 25, 29, 30, 36, 37, 38). But note the following points regarding verse 30 that refutes Oneness theology:
No agreement in conservative recognized Christian scholarship with a Oneness interpretation. Neither historically nor contemporaneously has any Christian writer interpreted John 10:30 in a modalistic (Oneness) way. Rather, all standard scholarly sources (patristics, commentaries, grammars, lexicons et al), interprets the passage in the plain intended way within the defining context: The person of the Son claiming equality with the distinct person of the Father.
Plain reading. Jesus simply says, “I and the Father ARE one.” Only by pretexting can one read something into this text beyond the simple plain reading.
The neuter adjective hen (“one”) is used—contextually indicating a unity of essence, not personal identity. If Jesus wanted to identify Himself as the Father (same person), He certainly could have used the masculine heis to indicate this (e.g., John 12:4; Rom. 3:10; 1 Tim. 2:5 et al.). In this passage, the Father and the Son are the subjects of the sentence (egō, “I,” Patēr, “Father”—both in the nominative case). The neuter adjective hen (“one”) is the predicate nominative and it precedes the plural verb esmen (“are”). The predicate nominative is describing the essential unity of Jesus and the Father. In others words, Jesus is explaining that the Father and Son are—one thing, not one person. In the context of unity, not identity of person, the same neuter adjective is used in John 17:21, where Jesus prays that His disciples “may be one [hen]” even as Jesus and the Father are one.
The plural verb esmen (“are”). Again, in sharp contrast to the false Oneness interpretation (Jesus is the Father), the Greek contains the plural verb esmen (“I and the Father are one”), and not a singular verb such as eimi (“am”) or estin (“is”) in which case, the passage would read: “I and the Father am/is one.” Furthermore, Jesus’ claim to deity is not merely found in verse 30. Rather, the passages leading up to verse 30 undeniably prove His claim. In verses 27-29, Jesus claims that He is the Shepherd that gives His sheep eternal life and no one can snatch them from His nor His Father’s hand (same words of YHWH in the LXX of Deut. 32:39).
 Greek grammarian A. T. Robertson comments on the application of the neuter hen in John 10:30: “One (hen). Neuter, not masculine (heis). Not one person (cf. heis in Gal. 3:28), but one essence or nature” (Robertson, Word Pictures).
 Note the same phrases used in both in Deuteronomy (LXX) and John: Deuteronomy 32:39: “And there is no one who can deliver ek tōn cheirōn mou [‘out of the hands of Me’].” John 10:28: “they will never perish; and no one will snatch them ek tēs cheiros mou [‘out of the hand of Me’].” Verse 10:29: “no one is able to snatch them ek tēs cheiros tou Patros [‘out of the hand of the Father’].”