ICC New Testament Commentary Regarding John 14:28

ὅτι ὁ πατὴρ μείζων μού ἐστιν. To this sentence theologians devoted close attention in the fourth century, but it would be out of place in a commentary on the Fourth Gospel to review the Arian controversy. It suffices to note that the filial relationship, upon which so much stress is laid in Jn., implies of itself that the Son is from the Father, not the Father from the Son. There is no question here of theological subtleties about what a later age called the “subordination” of the Son, or of any distinction between His οὐσία and that of the Father. But, for Jn., the Father sent the Son (see on 3:17), and gave Him all things (see on 3:35). Cf. Mark 13:32, Php 2:6, 1 Corinthians 15:27, for other phrases which suggest that ὁ πατὴρ μείζων μού ἐστιν is a necessary condition of the Incarnation. It is the same Person that says “I and my Father are one thing” (10:30), who speaks of Himself as “a man who hath told you the truth which I have heard from God” (8:40).1 See on 5:18, 32.