If you are willing to start an honest study on the subject of the Trinity, here are the verses shared by the commenter and the commentary on each verse (from the REV):
“Whoever has seen me has seen the Father.” The consistent theme throughout the book of John is that Jesus reveals God the Father to the world (John 1:18; 9:3; 14:9; 15:15; 17:6, 26). This simple truth demonstrates that Jesus is someone different from God. Many Trinitarians or Oneness believers see equivalence between Jesus and God in the Gospel of John, however, the author seeks to show how Jesus reveals the Father, not how Jesus is the Father. Knowing this helps the reader understand what Jesus means by phrases like, “whoever has seen me has seen the Father,” (John 14:9) and “I am in union with the Father and the Father is in union with me” (John 14:11). Neither of these phrases states that Jesus is the Father, nor should they be understood that way. Rather, these verses, when properly seen in light of the rest of the Gospel, demonstrate that God was working so powerfully through Jesus and Jesus was demonstrating God’s character so clearly that when one looked at Jesus, it was as if you were looking at the Father. This concept is not too difficult to grasp, as we use language similar to this in our modern culture. For instance, if a son is displaying a characteristic similar to his father (named Jim), we might say, ‘You’re just like your Dad,’ or, ‘Jim, is that you?’ or, ‘I see your Dad in you.’ No one takes that to mean the son literally is Jim, but that he resembles Jim in some ways. This is how we should understand Jesus’ statements of his similarity with his Father. Jesus never intends to teach that he is his Father, because he sees God his Father as someone different from himself (John 10:29; 14:28; 20:17), and he reveals his Father clearly through his works and teachings (John 14:10). This phrase in John 14:9 is also very helpful for understanding what Thomas may have meant in John 20:28 when he said to Jesus, “My Lord and my God.” Since Jesus taught Thomas here in John 14:9 that, “Whoever has seen me has seen the Father,” this is likely what Thomas was finally realizing in John 20:28. He was not realizing that Jesus was the Father, as Jesus had never taught Thomas that. Jesus taught Thomas that the Father was someone different from himself (John 14:6, 12, 16, 24; etc.). Rather, Thomas was realizing that the Father was “in union with” Jesus (John 14:11), that the Father was working in Jesus (John 14:10), and that Jesus’ words were the Father’s words (John 14:24). So, Thomas was realizing that the Father could be seen in Jesus, and thus could say, “My Lord and my God” (John 20:28). REV
Does the commonly accepted translation of Matthew 28:19 prove the existence of the Trinity? No. The mention of the Father, Son, and holy spirit together in one context only shows that these three exist. The doctrine of the Trinity that states there are three “Persons” in one God was not codified until AD 381. The Council of Nicea in AD 325 merely decided that Jesus was God, and did not make the Holy Spirit into a “third Person” in the Trinity. Also, there is a debate about whether the English translation of Matthew 28:19 should read “Holy Spirit” or “holy spirit” (the biblical evidence supports “holy spirit”), but in any case, there is no presentation in Matthew 28:19 of any formal doctrine of the Trinity. The doctrine of the Trinity states that the Father, Son, and “Holy Spirit” together make “one God” and that the three “Persons” are co-equal and co-eternal, and that doctrine is not stated in this verse. This verse refers to three, but never says they are “one.” If the phrase about the Father, Son, and holy spirit is original, then the three things this verse refers to are: God the Father; His Son the Lord Jesus Christ; and the holy spirit, a “gift” from God (cf. Acts 2:38). REV
That the word “in” refers to a relationship, a very close relationship, is clear from Jesus elucidating his teaching by using the same vocabulary and speaking of a branch being “in” a vine: “Live in me, and I will in you. As the branch is not able to bear fruit by itself unless it lives in the vine…” (John 15:4). The branch is not “inside” the vine, nor is “in” referring to being of the same mystical essence. It is a simple truth that the branch is in union with the vine; in an intimate relationship with it and united for the same purpose: to produce fruit. Similarly, God and Christ are in an intimate relationship and are in union with each other, and believers are to be in union with them. A few English versions make the relationship between God, Christ, and us somewhat clearer by translating the en (in) as “in union with,” or “unified with” instead of simply “in.” So, for example, in John 10:38, Charles Williams’ translation reads, “the Father is in union with me and I am in union with the Father” (he also uses “in union with,” rather than just “in” in other places in John). The New Testament translated by Edgar Goodspeed also uses “in union with” in John 10:38; 14:10-11, 20; and “united with” in John 15:4-7). The Complete Jewish Bible by David Stern also reads, “united with” instead of just “in” in John 10 and 14. The New English Bible uses “united with” in John 15:4. The point is that when the Bible says that the Father, Jesus, and believers are “in” each other, or being “one,” it refers to being in an intimate relationship with each other; being in union with each other.
"And the helper, the holy spirit, which the Father will send in my name, IT will teach you all things and bring to your remembrance all that I said to you." “And.” The Greek word de (#1161 δέ) can express a small contrast, but can also just express a change of subject. In this case, “but” is too strong a contrast. Some English versions leave the de untranslated and just start the English sentence with the subject, the Helper (cf. CEB), Others translate it “And.” Jesus was speaking with his disciples while he was still alive, and his point was that after he was personally gone from his disciples, the Helper would teach them what it heard. “the holy spirit.” The Greek text has no article “the” but it is supplied in the REV for clarity. The “the” is added in English due to its reference in the immediate context. This refers to the holy spirit that is the gift of God. [For more information on the holy spirit and uses of “holy spirit,” see Appendix 7: “What is the Holy Spirit?” and also see Appendix 15: “Usages of ‘Spirit.’”] “in my name.” In this context, the phrase “in my name” means “in connection with me.” The phrase is used that way many times in Scripture. The specific nature of the connection must be determined from the context (e.g., Matt. 18:5, 20; 24:5; Mark 9:37, 39; John 15:16). REV