Groups such as the Jehovah's Witnesses and Oneness Pentecostals dispute the doctrine of the Trinity. Some specifically claim that Tertullian, Origen and Theophilus of Antioch gave evidence against it. This is not true.
The Church's Scriptures that support the Blessed Trinity:
Philip asks Jesus to show them the Father.
8 Philip said to him, "Lord, show us the Father, and we shall be satisfied." 9 Jesus said to him, "Have I been with you so long, and yet you do not know me, Philip?
He who has seen me has seen the Father; how can you say, `Show us the Father'?
10 Do you not believe that I am in the Father and the Father in me? The words that I say to you I do not speak on my own authority; but the Father who dwells in me does his works. 11 Believe me that I am in the Father and the Father in me; or else believe me for the sake of the works themselves. 12 "Truly, truly, I say to you, he who believes in me will also do the works that I do; and greater works than these will he do, because I go to the Father.
John 14:8-12
Knowing the Father is knowing His Son, Jesus
27 All things have been delivered to me by my Father; and no one knows the Son except the Father, and no one knows the Father except the Son and any one to whom the Son chooses to reveal him.
Matthew 11:27
All Fatherhood comes from God, the Father so you may be strengthened through His Spirit, in Christ, His Son.
14 For this reason I bow my knees before the Father, 15 from whom every family in Heaven and on earth is named, 16 that according to the riches of his glory he may grant you to be strengthened with might through his Spirit in the inner man, 17 and that Christ may dwell in your hearts through faith; that you, being rooted and grounded in love,
Ephesians 3:14-17