Before Our Lord Jesus Christ ascended into Heaven, He commissioned His Apostles by saying,
||"All power is given to me in heaven and in earth. Going therefore, teach ye all nations; baptizing them in the name of the Father, and of the Son, and of the Holy Ghost. Teaching them to observe all things whatsoever I have commanded you: and behold I am with you all days, even to the consummation of the world." (St. Mat.28:18-20, Douay Bible).||
Grammatically, we can say that there is something wrong with this statement because if you are going to mention many persons, you must say " in the names of my father and my mother, etc.". But when Jesus ordered his Disciples, He said "baptizing them in the NAME of the Father, and of the Son, and of the Holy Ghost."(emphasis mine). Theologically, Jesus was right because the Father, the Son and the Holy Ghost He is referring to refers only to One God, the Blessed Trinity.
St. John wrote,
||"And there are three who give testimony in heaven, the Father, the Word, and the Holy Ghost. And these three are one." (1 Jn.5:7)||
The Father is not another God. The Son is not another God. The Holy Ghost is not another God. The Father, the Son and the Holy Ghost are One. Does it mean the Father, the Son and the Holy Ghost are one and the same Person? No. These 3 are distinct Persons in One Divine Nature. Divinity is a Nature. When we talk about the Divine Father, we are talking about God the Father who is the First Person of the Blessed Trinity. The Son is the Second Person and the Holy Ghost is the Third Person of the Triune God.
There are 3 Divine Persons in One Divine Nature. There is only One God: the Father, the Son and the Holy Ghost.
