The Bible contains statements against the Trinity, like this 3-in-1 verse against the Trinity..
John 17:3 And this is eternal life, that they know you, the only true God, and Jesus Christ whom you have sent.
1. Jesus said the Father is the only true God!
2. Jesus cannot be the only true God that sent, because Jesus said he did not send himself! John 7:28-29; 8:42.
3. Jesus said this is what eternal life looks like for all of eternity, knowing only two, the Father and the Son, just the two persons!
Three witnesses in one verse against the Trinity! In the most important prayer, which actually happens to include the first most important commandment of all Mark 12:28.
And you cannot fit a 3-in-1 God into that confession of the Lord Jesus Christ. This is what the Lord said, not someone who wrote something after the time of the disciple John, who wrote, "Children, it is the last hour, and as you have heard that antichrist is coming, so now many antichrists have come. Therefore we know that it is the last hour." - 1 Jn. 2:18, and Jn. 12:31 Now is the judgment of this world; now will the ruler of this world be cast out.
The Bible is extremely clear that God is not a Trinity, even specifically (the number and the name Trinity, the 3-in-1 God, is in the Bible). The Bible states clearly that God is a Single Personal Pronoun, one single Person. So, whenever we read things like "Let Us make," or the plurality of God, it obviously must mean something other than another Person, because there is only one true single He God Person! That is our foundation, clearly spoken, in the New Testament!
God is our judge (Ps 50:6, Eccl 12:14) Jesus is our judge (2Tim 4:1, Rev 20:12)
God is the temple of the New Jerusalem (Rev 21:22) Jesus Christ (the Lamb)is the temple of the New Jerusalem (Rev 21:22)
God is the first and the last (Is 44:6, 48:12) Jesus is the first and the last (Rev 22:13)
God is the beginning and the end (Rev 21:6) Jesus is the beginning and the end (Rev 22:13)
Only God can forgive sins (Lk 5:21) Jesus forgives sins (Lk 5:20)
God is our hope (Ps 71:5) Jesus is our hope (1Tim 1:11)
God is eternal(Deut 33:27) Jesus is eternal (Is 9:6, Heb 1:10-11)
God will come with the holy ones (Zech 14:5) Jesus will come with the holy ones (1Thess 3:13)
Only God is our savior (Is 43:11) Jesus is our savior (Tit 2:13, 2Pet 1:1)
God is the creator of the universe (Is 44:24, Jer 27:5) Jesus is (Jn 1:3)
To God, every knee will bow and every tongue confess (Is 45:22-23) To Jesus (Phil 2:10-11)
God is the same and His years will have no end (Ps 102:27) Jesus is the same and His years will have no end (Heb 1:12)
God is immutable (Mal 3:6) Jesus is immutable (Heb 13:8)
God is over all (Ps 97:9) Jesus is over all (Jn 3:31)
The spirit of God dwells in us (Rom 8:9) The spirit of Jesus dwells in us (Gal 4:6)
God is a stone of offence and a stumbling block (Is 8:14) Jesus is a stone of offence and a stumbling block (1Pet 2:8)
God is our shepherd (Ps 23:1) Jesus is our shepherd (Jn 10:11, 1Pet 5:4, Heb 13:20)
God is our Lord of Lords (Deut 10:17, Ps 136:3) Jesus is Lord of Lords (Rev 17:14)
God is our only rock (Is 44:8, Ps 18:2, 94:22) Jesus is our rock (1Cor 10:4)
No one can snatch us out of Gods hand (Deut 32:39) No one can snatch us out of Jesus hand (Jn 10:28)
God is the horn of salvation (2Sam 22:3) Jesus is the horn of salvation (Lk 1:68-69)
God renders according to our works (Ps 62:12) Jesus renders according to our works (Mt 16:27, Rev 22:12)
God loves and corrects (Prov 3:12) Jesus loves and corrects (Rev 3:19)
Gods words will stand forever (Is 40:8) Jesus words will stand forever (Mt 24:35)
God is the eternal light (Is 60:19) Jesus is the eternal light (Jn 8:12, Rev 21:3)
God seeks to save the lost (Ez 34:16) Jesus seeks to save the lost (Lk 19:10)
Paul is a slave of God (Tit 1:1) Paul is a slave of Christ (Rom 1:1)
God raised Jesus from the dead (Gal 1:1) Jesus raised himself from the dead (Jn 2:19-21)
God is our guide (Ps 48:14) Jesus is our guide (Lk 1:79)
God is our deliverer (Ps 70:5, 2Sam 22:2) Jesus is our deliverer (Rom 11:26)
God is called God (Is 44:8) Jesus is called God (Jn 20:28)
God is the king of Israel (Is 44:6) Jesus is the king of Israel (Mt 27:42, Jn 1:19)