Is the concept of God in Christianity (the Trinity) three Gods or One
Yours is an age old question, which stems from a basic misunderstanding.
We have one God in three persons, but that is confusing unless we also understand that God is a Spirit. To explain that we must also understand the difference between the Spiritual realm and the Material realm.
In our material realm certain rules apply which do not apply in the Spiritual realm. For example; in the Material realm things have mass, which means that according to the laws of physics two objects cannot occupy the same space at the same time; that is not true in the Spiritual realm. The following Scripture shows this as effectively as anything I could say:
All scripture is quoted from the King James translation, unless otherwise noted.
Mark 5:2 through 10 And when he was come out of the ship, immediately there met him out of the tombs a man with an unclean spirit, 3 Who had his dwelling among the tombs; and no man could bind him, no, not with chains: 4 Because that he had been often bound with fetters and chains, and the chains had been plucked asunder by him, and the fetters broken in pieces: neither could any man tame him. 5 And always, night and day, he was in the mountains, and in the tombs, crying, and cutting himself with stones. 6 But when he saw Jesus afar off, he ran and worshipped him, 7 And cried with a loud voice, and said, What have I to do with thee, Jesus, thou Son of the most high God? I adjure thee by God, that thou torment me not. 8 For he said unto him, Come out of the man, thou unclean spirit. 9 And he asked him, What is thy name? And he answered, saying, My name is Legion: for we are many. 10 And he besought him much that he would not send them away out of the country.
Here we see that many spirits were inhabiting the body of one man, and if we continue with the Scripture we find that there were about two thousand of them.
Mar 5:11 through 13 Now there was there nigh unto the mountains a great herd of swine feeding. 12 And all the devils besought him, saying, Send us into the swine, that we may enter into them. 13 And forthwith Jesus gave them leave. And the unclean spirits went out, and entered into the swine: and the herd ran violently down a steep place into the sea, (they were about two thousand;) and were choked in the sea.
We also need to look at the words, Jesus said " What is thy name?" and the devils answered, " My name is Legion: for we are many."
It is noteworthy that Jesus used the singular form 'thy' in asking the name, and it is likewise notable that the devils (plural) used the singular form 'my' in answering even though adding that they were many.
There is no difference between those many spirits being one (legion) and God being three; Father, son, and Holy Ghost.
In the Spiritual realm more than one can occupy the same space at the same time, and be known by a single name.
Hope this helps.