Can a person be a baptist or remain a baptist if he/she doesn't believe in the (baptist) trinity doctrine?
Can that person be saved?
Thanks for this great question. The doctrine of the Trinity is an Orthodox Doctrine, not only embraced by Baptists, but by most Evangelicals. The Bible is clear that this doctrine is essential to Salvation.
1 John 2:20–24 (AV)
20 But ye have an unction from the Holy One, and ye know all things. 21 I have not written unto you because ye know not the truth, but because ye know it, and that no lie is of the truth. 22 Who is a liar but he that denieth that Jesus is the Christ? He is antichrist, that denieth the Father and the Son. 23 Whosoever denieth the Son, the same hath not the Father: (but) he that acknowledgeth the Son hath the Father also. 24 Let that therefore abide in you, which ye have heard from the beginning. If that which ye have heard from the beginning shall remain in you, ye also shall continue in the Son, and in the Father.
The unction is from the Holy Spirit. To deny the Christ is to deny both the Father and the Son... so we have the entire Trinity involved.
1 John 5:7 (AV)
7 For there are three that bear record in heaven, the Father, the Word, and the Holy Ghost: and these three are one.
Most Baptist Churches require that you believe basic Baptist beliefs in order to join their church. I can tell you that if you were in our fellowship, you would not be able to join our church if you did not agree with our doctrinal statement.
I hope that this helps you.