The book of Hebrews begins with awesome words about the Lord Jesus Christ and His importance in God’s unfolding revelation.
Long ago, at many times and in many ways, God spoke to our fathers by the prophets, but in these last days he has spoken to us by his Son, whom he appointed the heir of all things, through whom also he created the world. He is the radiance of the glory of God and the exact imprint of his nature, and he upholds the universe by the word of his power. After making purification for sins, he sat down at the right hand of the Majesty on high, having become as much superior to angels as the name he has inherited is more excellent than theirs. Hebrews1:1–4
I think the Christology in the book of Hebrews is exceedingly high; in fact, it is one of the chief reasons why the early church was inclined to affirm the deity of Christ. Here we see Christ again described as the Son of God and as the agent of creation, who presents a vastly superior revelation than did the prophets of the Old Testament.
But the author also presents the concept that the Son of God is “the radiance of the glory of God and the exact imprint of his nature.” This is a clear reference to Jesus’ deity, but the author is also distinguishing the Son of God from the Father in terms of the idea of personhood. The Father’s person is expressed in the person of the Son. So even though both the Father and Son are divine, the author of Hebrews here sets forth the idea of a personal distinction in the Godhead.
Jesus himself alludes to the trinity:
Jesus replied, Have I been with all of you for so long a time, and do you not recognize and know Me yet, Philip? Anyone who has seen Me has seen the Father. How can you say then, Show us the Father?
10 Do you not believe that I am in the Father, and that the Father is in Me? What I am telling you I do not say on My own authority and of My own accord; but the Father Who lives continually in Me does the (His) works (His own miracles, deeds of power).
11 Believe Me that I am in the Father and the Father in Me; or else believe Me for the sake of the [very] works themselves. [If you cannot trust Me, at least let these works that I do in My Father’s name convince you.]
John 14:9–11