Short answer
– From a mainstream evangelical perspective, the most likely author of the Gospel passage containing John 10:14–15 is John the Apostle — the “disciple whom Jesus loved” (the Beloved Disciple). Evangelicals typically hold that this apostle, an eyewitness and close companion of Jesus, wrote the Fourth Gospel late in the first century (c. 90–100 AD), probably from Ephesus.

Why evangelicals identify John the Apostle as the author
– Internal claim of eyewitness connection: the Gospel repeatedly identifies a close, eyewitness disciple (the “disciple whom Jesus loved”) and ends by saying, “This is the disciple who testifies to these things and who wrote them” (John 21:24). Evangelicals take this as an authorial claim linking the book to an eyewitness.
– Early church testimony: Early Christian writers — especially Irenaeus (late 2nd century), who knew Polycarp (a disciple of John), and other Fathers such as Papias (as quoted by later writers), Clement of Alexandria, and Tertullian — attribute the Gospel to John the son of Zebedee.
– Unity of style and theology: The Fourth Gospel displays consistent Johannine vocabulary and theological emphases (e.g., “I am” sayings, focus on eternal life, intimate Father–Son language) that match the Johannine letters (1–3 John). Evangelicals argue that such unity is best explained by a single author with firsthand experience of Jesus.
– Eyewitness and apostolic authority: Because the Gospel presents detailed, intimate scenes (the disciple at the cross, the breakfast by the Sea of Galilee, close interactions with Jesus), evangelicals see an eyewitness apostle as the most plausible source, giving the Gospel apostolic credibility and authority.

Biographical notes evangelicals emphasize about John
– John son of Zebedee: one of the Twelve, brother of James, a fisherman called by Jesus (see the Synoptics).
– Part of Jesus’ inner circle: present at Peter’s confession, the Transfiguration, and the raising of Jairus’s daughter; close enough to the Lord to be called “the disciple whom Jesus loved.”
– Later ministry: tradition places him in Ephesus where he ministered and (according to tradition) wrote the Gospel and the three epistles. Revelation’s authorship is discussed separately (John of Patmos) and sometimes linked to the same John, though evangelicals differ on that point.

How this relates to John 10:14–15
– John 10:14–15 (“I am the good shepherd; I know my sheep and my sheep know me… I lay down my life for the sheep”) comes from the Gospel’s “Good Shepherd” discourse. Evangelicals read this as reliable teaching recorded by an eyewitness apostle who knew Jesus’ words and ministry personally and who aimed to show Jesus’ identity and saving work (cf. John 20:31).

Objections and evangelical responses (brief)
– Some critical scholars argue for an anonymous “Johannine community” or a later editor/author. Evangelical responses stress: the Gospel’s own eyewitness claim, early patristic attributions to John, the unity of the text, and the difficulty of explaining the detailed, personal content without an actual eyewitness author.
– On dating: critics who push a very late date are answered by evangelicals pointing to early external testimony and the Gospel’s stability in early Christian use.

Further reading (evangelical-friendly)
– D. A. Carson, The Gospel According to John (Pillar Bible Commentary)
– Leon Morris, The Gospel According to John (Tyndale New Testament Commentaries)
– F. F. Bruce, The Gospel of John (New International Commentary on the New Testament)
– For history of early attestation: Raymond E. Brown’s introductions (noting Brown is often more critical but is widely read)

If you’d like, I can:
– Summarize the evidence in more detail,
– Compare the traditional view to critical alternatives,
– Or show how John 10:14–15 fits into the larger Johannine theology.