I would like to ask what has been said about the nature of the trinity:
that their is one God who is in three persons. I have heard a biblical
scholar that said there are three God having different personalities. So
what is the truth about it?

Thousands of volumes and, believe it or not, dozens of wars have been
fought over this question. I would not be so arrogant as to think that I
can add a lot to this discussion. The question of the nature of God is
broad and deep. Let me mention a few things which are definitely not
correct and give at least a foundation on which you can base your own
study and thinking.

First, there are not three Gods. “Hear, O Israel: The Lord our God the
Lord is one.” (Deuteronomy 6:4). The New Testament does not introduce
polytheism. Jesus said, “I and the Father are one.” (John 10:30). Jesus
was not created by the Father, but existed with him from the beginning.
“Before Abraham was born, I AM” (John 8:58). The same could be said of the
Holy Spirit. In Genesis 1:2, the Holy Spirit is described as being an
agent in the creation of the world. Jesus, the Son is also described as
being an agent in the creation and the holding together of the world.
Colossians 1:16 says of Jesus, “For by him all things were created: things
in heaven and on earth, visible and invisible, whether thrones or powers
or rulers or authorities; all things were created by him and for him.”
Colossians also says of Jesus that “He is before all things.” (Colossians
1:17).

What about the “trinity?” It is worth bearing in mind that nothing like
the word trinity is found in the Bible. The word was coined by Roman
Catholic theologians to explain the nature of God. There is nothing really
wrong with the word trinity, but it comes with some theological baggage
within Roman Christianity which I am personally not comfortable with. I
tend not to use this word to describe God because of the theological
implications within Catholicism with which it tends to be associated.

Nevertheless, the implication of the word trinity is that God is somehow
three and one at the same time. It is extremely difficult to put the
Bible’s description of God into simple terms, but this comes about as
close as any. In John 1:1, Jesus is described in the following well-known
statement: “In the beginning was the Word, and the Word was with God, and
the Word was God. He was with God in the beginning.” Verse fourteen
continues, “The Word became flesh and lived for a while among us. We have
seen his glory, the glory of the one and only Son…” John describes Jesus
as the Son who is with God and who at the same time is God. In human terms
this description is not logical. Nevertheless, this is how God describes
himself. Some phrases which seem to work fairly well to describe God are,
three aspects of God in one or perhaps three emanations of the godhead. I
believe the description you quote from a “scholar” that God has three
personalities is not appropriate. I see no difference in “personality”
between the Father, the Son or the Spirit. Some have tried to describe the
three-in-one nature of God using the analogy of the three forms of water:
ice, liquid water and steam, but as a chemist myself, I believe that this
analogy really does not help at all.

Theologians can write their treatises, scholars can accumulate sources
claiming to explain the three-fold nature of God, skeptics can scoff at
this doctrine, but in the end, the believer is left to ponder the awesome
and inscrutable nature of God. It would take a lifetime to take it in.
Fortunately, we do not have to have a completely understandable and
logical description of God to know that he loves, that he died for us and
that we must come to him and repent of our sins to be saved and to avoid
separation from God forever. I suggest you spend most of your energy
sticking to the basics of obeying your creator, but continue at times to
step back and consider the awesome nature of our God.

John Oakes, PhD