In the seven letters that Paul clearly wrote, did he write that Jesus is God? In other words, did he teach that God existed in the form of three persons, Father, Son and Holy Spirit. Can you give me verses for this?
To be honest, I do not want to answer this question. It feels like a bit of a “trick” question. Not that I am accusing you of trying to trick me! There is a premise behind your question, which is that Paul did not write the other books. I do not agree with this premise. It is a bit like this. How do you explain the fact that you killed your wife? Well, I did not kill my wife, so any answer I give will give credence to a theory that I do not agree with. I believe that Paul wrote Titus and in Titus Paul called Jesus “our great God and Savior.” I believe that Paul wrote Colossians and in Colossians Paul said that in Christ the fullness of deity dwelt in bodily form. (Colossians 2:9) So, because I do not accept the premise, the question is a red herring in my opinion.
Nevertheless, among the many passages which prove that Paul thought of Jesus as God, some of them come from the supposed “genuine” letters of Paul. For example, there is 1 Corinthians 2:16. “Who has known the mind of the Lord so as to instruct him? But we have the mind of Christ. Here, Paul is quoting from Isaiah 40:3, which is undoubtedly a reference to Yaweh, but is applying it equally to Christ. He is identifying Jesus with YHWH. A similar idea is found in 1 Cor 8:6 in which Paul says that there is one God from whom all things come, but then in the same verse says that all things came from Christ. Here he is explicitly equating Christ with God. Many passages of this sort can be listed.
It is obvious that Paul never used the word trinity. The word is not in the New Testament, but that Paul thought of Jesus Christ as God, whether in the supposedly “genuine” letters or in the other letters that he also wrote, Paul clearly sees Jesus as being deity, God-in-the-flesh. There are plenty of verses in which Paul described the Spirit as God as well, such as Romans 8:11. This attempt to put some of Paul’s letters into debate with others of Paul’s letters is not helpful, in my opinion. Paul expresses the same idea in various ways in his letters, as does any author, but his view of Christ is consistent throughout. All Scripture is inspired by God–by the same God.