ST POLYCARP, BISHOP OF SMYRNA, MARTYR—7?-166 Feast: February 23
Jesus himself declares that he is Yahweh ("I AM,"). In John 8:58, when questioned about how he has special knowledge of Abraham, Jesus replies, "Truly, truly, I say to you, before Abraham was, I AM." His audience understood exactly who he was claiming to be. "So they took up stones to throw at him; but Jesus hid himself, and went out of the temple" (John 8:59).
With the personal name of God, Yahweh, being applied to both the Father and the Son, it is almost certainly applied to the Spirit, and thus to all three members of the Trinity.
The parallelism of the Father, the Son, and the Spirit is not unique to Matthew’s Gospel, but appears elsewhere in the New Testament (e.g., 2 Cor. 13:14, Heb. 9:14), as well as in the writings of the earliest Christians, who clearly understood them in the sense that we do today—that the Father, the Son, and the Spirit are three divine persons who are one divine being (God).