Can person remain a baptist if one doesn't believe in the trinity doctrine? Can that person be saved?
Thank you for the question. I suspect the answer depends on what is meant by the trinity doctrine. All mainstream Christian denominations believe in one God who exists in three persons who interact in perfect unity. That Jesus is God is clearly there in scripture. In John's Gospel Jesus frequently uses the phrase 'I am' (eg Good Shepherd, the way the truth an the life etc.)and in John 8:58 & 59 He uses the startling words, 'Before Abraham was born I am.' The Pharisees knew he was claiming to be God. That is why they tried to stone Him. Jesus was using the name of God revealed by God to Moses. It is also clear that the Holy Spirit is more than just an impersonal force as in scripture He thinks, guides and can be grieved. That Jesus and the Holy Spirit are God is clear. How that relationship works is less clearly defined and the term 'trinity', which is not itself biblical, is simply the short hand way of expressing that Father, Son and Spirit are all God and yet one God.
Can someone be a Baptist and not agree with this? It is hard to see how as this is a foundation doctrine of all mainstream churches, though the understanding of how it fits together may vary.
Can that person be saved? That is a harder question. Romans 10:9 has the confession of Jesus as Lord as central to salvation. The word Lord is a reflection of the Hebrew 'Addonai' which is applicable to God the Almighty. Thus the centrality of Jesus as God seems vital. Beyond this all I can add is that salvation is by grace through faith alone and the judging of individuals I will leave to God.
I hope these comments are of some help. May God bless and lead you.