How is there a Father Son and Holy Spirit?
In the present generation, many are confused about the Christian concept of Triune God because mathematically this is impossible. However, in the Bible we find many references which justify the fact that even though God is one, He manifests Himself as a Trinity. The teaching of the Bible concerning the Trinity might be summarized thus. God is a Tri-unity, with each Person of the Godhead equally, fully and eternally God. Each is necessary and each is distinct, yet all are one. The three Persons appear in a logical, causal order. The Father is the unseen, omnipresent Source of all being, revealed in and by the Son, experienced in and by the Holy Spirit. The Son proceeds from the Father and the Spirit from the Son. With reference to God's creation, the Father is the Thought behind it, the Son is the Word calling it forth, and the Spirit is the Deed making it a reality. According to the Gospel of St. Matthew, when Jesus Christ commanded his disciples to baptize people into Him, he used the term "in the name of the Father, the Son and the Holy Spirit". He did not say "in the names of" (a plural tense), instead he said "in the name of" as if to denote a single person, a Triune God. Jesus told his disciples: "I and the Father are one." In His prayer he said to the Father, "Holy Father, protect them by the power of your name, the name you gave me, so that they may be one as we are one." Further, in the book of Acts, the Holy Spirit is also addressed as the Spirit of Jesus. Even though they have a separate identity, function and nature, essentially they are one.
I would like to illustrate this fact by using a simile. A mango tree has three parts, the root, the shoot which carries the branches and leaves, and the fruit. All these parts are morphologically and anatomically different because they have to perform different functions. However, not only is the basic genetic makeup of every individual cell of each part of the tree identical but the life of the tree is also considered to be one. We do not address the tree as three different beings instead we address it as a single being with three different parts. We also know that even though every part of the tree retains its individuality all these parts work in tandem with one another and within a healthy tree there is no scope of disharmony. Similarly, God of the Bible is a Triune God. He has three distinct personalities: the Father, the Son and the Holy Spirit. Although they all retain their individuality, they are essentially the same Spirit-being, just like how each and every cell of a mango tree carries a common genetic makeup and life.
The root taps water and essential minerals for the whole tree and grounds it so that it can stay upright even in hostile conditions. Therefore it is located at the bottom of the tree, goes deep into the soil and remains below the ground. The shoot reveals the existence and character of the tree to those who look at it from the ground level. It also serves to channelize water and minerals to the branches which hold the leaves that trap sunlight in order to bear fruit which in turn propagates the seed of the tree. Above all, it is the fruit that highlights the character of the tree. In the words of the Lord, "Every tree is known by its fruit. A good tree cannot bear bad fruit, and a bad tree cannot bear good fruit."
Likewise, God also has three personalities: the Father, the Son and the Holy Spirit. They enjoy an independent existence but are interdependent and carry out different functions for a common will because they contain the same spiritual life within them. The Father who is greater than all can be compared to the root which remains hidden but holds the whole tree together, and also acts as the source of nutrition to every other part of the tree. The shoot of the tree that reveals its existence can be compared to the Son who has revealed the character of the Father to human beings. And the Holy Spirit who dwells in the hearts of the people, who believe in Christ, can be compared to the fruit of the tree. It's the Holy Spirit that helps people to taste and know that the Lord is good. The Holy Spirit also sows in them the word of truth, the seed of life. If a mango tree that has three parts specialized to perform different functions can be considered as one, then why can't God who has three different personalities, specialized to do different functions also be considered as one? Moreover, the whole mango tree, with all the three parts comes forth from a single seed, likewise the whole personality of God can summarized as a seed, 'a word', the expression which St. John used in the first chapter of his gospel, "In the beginning was the word, the word was with God and the word was God."