Trying to explain the doctrine of the Trinity has kept many a theologian busy down the centuries. One helpful picture is to imagine the sun shining in the sky. The sun itself – way out there in space, and unapproachable in its fiery majesty – is the Father. The light that flows from it, which gives us life and illuminates all our lives, is the Son. The heat that flows from it, and which gives us all the energy to move and grow, is the Holy Spirit. You cannot have the sun without its light and its heat. The light and the heat are from the sun, are of the sun, and yet are also distinct in themselves, with their own roles to play.
The Bible makes clear that God is One God, who is disclosed in three persons: Father, Son (Jesus Christ) and Holy Spirit. For example:
Deuteronomy 6:4: ‘Hear O Israel, The Lord our God, the Lord is one.’
Isaiah 45:22: ‘Turn to me and be saved… for I am God, and there is no other.’
Genesis 1:1-2: ‘In the beginning God created…. and the Spirit of God was hovering…’
Judges 14:6: ‘The Spirit of the Lord came upon him in power…’
John 1:1-3: ‘In the beginning was the Word, and the Word was with God, and the Word was God. He was with God in the beginning. Through Him all things were made; without Him nothing was made that has been made.’
Luke 24:49 actually manages to squeeze the whole Trinity into one sentence. Jesus tells His disciples: ‘I am going to send you what my Father has promised; but stay in the city until you have been clothed with power (the Holy Spirit) from on high.’
In other words, the sun eternally gives off light and heat, and whenever we turn to its brilliant light, we find that the warmth and life there as well.
(Source : Parish Pump)