In considering the Trinity presented in the New Testament, a particularly useful analogy to explore is that of the Sun, which itself is employed a number of times in the New Testament.
The Sun is the glorious power from which all human life, and nature, is sustained, both knowingly and unawares, and is a most perfect and beautiful symbol for God.
The sun sheds its life-giving influence upon the world through its rays of light, warming and illuminating the earth and its peoples; by these rays, night is turned into day, and all work and life is empowered. These life-giving rays spreading from the Sun out into the world, are the symbol of the Holy Spirit, being the creative flowing of God into the world of existence; also called the Word of God: for the Holy Spirit is the direct commanding of God through which He says 'Be' and it is.
These rays of light travel into the world by virtue of a pure and stainless medium that mediates their spiritual power from the world of God in to the world of man. This mediator is Christ, and in the symbol of the sun He is the clear open space through which the sunlight of the Holy Spirit travels to the world, the windows through which the Spirit enters into the daily homes of people's lives. The spiritual mediation of God to mankind is through virtue of a perfectly pure and devoted nature wholly devoid of ego, called sinless, through which the divine influence may travel to man's world unsullied. Of primary importance is the mediation of God to the inner spirit of each individual, so that they are revolutionised in spirit, 'a new creation', though to all outer worldly eyes no change appears: "Therefore if any man be in Christ, he is a new creature: old things are passed away; behold, all things are become new" (2Co 5:17; Gal 6:15). John the Baptist referred to Jesus' mediating the Spirit to man as 'baptizing' people with Spirit: "He that sent me to baptize with water, the same said unto me, Upon whom thou shalt see the Spirit descending, and remaining on him, the same is he which baptizeth with the Holy Spirit." (Jn 1:31-33)
The station of mediator of the Holy Spirit, is one of a humble servant conveying the glorious Spirit from the Master Fashioner to the world: thus in Acts, he is called the Servant of God (e.g. Act 3:13, 3:26, 4:27, 4:30), and the same is included more lovingly in the title 'Son of God'. Hebrews depicts this humble servitude vividly: "During the days of Jesus' life on earth, he offered up prayers and petitions with loud cries and tears to the one who could save him from death, and he was heard because of his reverent submission... he learned obedience from what he suffered, and once made perfect... was designated by God to be high priest in the order of Melchizedek" (Heb 5:7).
Christ's greatness in pure mediation of the Holy Spirit into the world of man, is like the greatness and perfection of a window in allowing the sun to shine through. It is forgiveable to curse the window as an object in itself, but not the light that shines through it. Thus Jesus says: "Whosoever shall speak a word against the Son of Man [Jesus], it shall be forgiven him: but unto him that blasphemeth against the Holy Spirit, it shall not be forgiven" (Lk 12:10) - just as you may speak ill of a flute, but if you abhor the music which plays through it, then you are denying the very creative breaths of the Master Musician. On the other hand, in recognising the purpose of the window in mediating the Light of the Sun, to curse the window is generally equivalent to abhoring the Light, and so through coming in God's name, to deny Jesus is to deny God (1 Jn 2:23), rather as to accept or deny Jesus' apostles when they come in Jesus' name is to accept or deny Jesus (Mk 9:41-42). These distinctions usually exist between a thing and its appointment in a role - it is forgiveable to throw eggs at Churchill, for as an individual he must forgive, but not forgiveable to throw them at the Prime Minister, for by doing so you are throwing them at the Queen and State: at the authorising order and authority. Thus it is not the mediator that is great, but the thing that is mediated and the authority that appoints it, is great. Making this quite clear, Jesus exclaims, "Why callest thou me good? there is none good but only God!" (Mk 10:18), and elsewhere, "My Father is greater than I" (Jn 14:28), and "My Father, who hath given to me, is greater than all, and no one is able to pluck out of the hand of my Father" (Jn 10:29), and "The servant is not greater than his lord; neither He that is sent greater than He that sent Him" (Jn 13:16), and "To sit on my right hand and on my left hand is not mine to give" (Mk 10:40), and, "But of that day [of return] and that hour knoweth no man, no, not the angels which are in heaven, neither the Son, but the Father," (Mk 13:32)
Whilst this embodiment of servitude and egolessness is what makes the mediator perfect, yet the window by being mediator can say quite earnestly, "Whoever looks at me, looks at the Sun"; and so Christ speaks words such as these: "He that seeth me seeth Him that sent me" (Jn 12:45), and, "He that hath seen me hath seen the Father" (Jn 14:9), and "No man hath seen God... the... Son... in the bosom of the Father... hath declared him" (Jn 1:18). By being the servant of God's glory into the world of man such that whoever gazes upon him gazes upon God, Jesus is called variously the "image", "likeness", "exact representation", and "mediator" of God and God's covenant, mediating the "brightness of His glory" (2 Co 4:4, Col 1:15, Heb 1:3, 1 Ti 2:5 etc). Jesus does not judge, yet because He mediates God's judgment, His judgment is right: "I judge no man. And yet if I judge, my judgment is true: for I am not alone, but I and the Father that sent me." (Jn 8:15-6; also 5:30)
Whilst Jesus explains that the Father is far greater than he, yet they are in perfect unison: "I and the father are one" (Jn 10:30). This is obviously not a unity of essense but a unison of attributes, for the Father is greater than he, knows the day and hour whilst the son does not, and determines who sits on the right and left of Jesus whilst the son does not. By being the 'image' and 'representation' of God, a unison of attributes is meant. This same unison Jesus requests also for his disciples: "that they may be one, even as we are one" (Jn 17:21-23)
The servitude and dependency of Jesus upon 'the one who could save him from death' (Heb 5:7) is inculcated throughout the gospels, with Jesus asserting that he is simply saying and doing whatever he is told to say and do by the Spirit, and knows only what he is told or shown: "The Son can do nothing of himself, but what he seeth the Father do: for what things soever he doeth, these also doeth the Son likewise," (Jn 5:19), and "I can of mine own self do nothing," (Jn 5:30), and "I do nothing of myself; but as my Father hath taught me, I speak these things" (Jn 8:28); "I speak that which I have seen with my Father" (Jn 8:38); "I have not spoken of myself; but the Father which sent me, he gave me a commandment, what I should say, and what I should speak... whatsoever I speak therefore, even as the Father said unto me, so I speak." (Jn 12:49-50), "the words that I speak unto you I speak not of myself: but the Father that dwelleth in me, he doeth the works" (Jn 14:10), "the word which ye hear is not mine, but the Father's which sent me" (Jn 14:24), "as the Father gave me commandment, even so I do" (Jn 14:31), "all things that I have heard of my Father I have made known unto you" (Jn 15:15).
When a man comes to visit you in a car, and goes away saying he will be back again in a few years, there is no intent as to whether he will be coming back in the same car or some other. You have to look out for the driver. He may have come by a Toyota, but if you insist he will return in a Toyota, you may miss him if he comes in a Porsche or a Lada. Jesus is the mediator of the Holy Spirit, and what he is says is just whatsoever the Holy Spirit wishes to communicate from God to Man. So when the Holy Spirit says that it will return again, this has no bearing on what vehicle it will choose to take - what name, colour, shape or form it will come by. The Jews were thrown by this same issue, expecting a clear promise of Elijah's return but getting John the Baptist (Lk 1:17) - for Elijah and John were merely mediators of the Holy Spirit. The driver - the Holy Spirit - returned as promised, but people were looking at the car. So in the Holy Spirit promising to return through the mouth of Jesus, people are again looking out for the car, and yet the Spirit promises of that time: "I will write upon him my new name" (Rev 3:12), and that it shall return in the clouds. Those that look in the material way will see just clouds not the Sun.
Speaking of the return of the Holy Spirit through a different vehicle at a time when his church would become corrupt and worldly with the influence of Jesus lost from people's hearts (a fact which occurred most particularly in the sixth century, and again recently), Jesus says of that future vehicle: "I shall beseech the Father, and He will provide you a different Intercessor, with the purpose that he remain with you for the age, the Spirit of Truth which society is unable to receive, such that it neither discerns it [the Spirit of Truth], much less knows it deeply... Now the Intercessor, the Holy Spirit which the Father will send in my name: that very one shall train you in all things, and put in your minds all things, which things I have conveyed to you... but I tell you truthfully, it benefits you that I stand aside: for if I do not, the Intercessor will not come among you; yet if I travel, I will send him on to you. And when he has arrived, it is he who will confront society on sinfulness, and regarding decency, and of a just reckoning... I have still many things to convey to you, but ye are unable to carry them at present. Howbeit, whensoever that one should appear, the Spirit of Truth, he will guide you into the whole truth: for he shall not utter from of himself; but as many things as he should hear, he will utter: and he will announce to you the things that are to come." (Jn 14-16)
All feedback appreciated - David Merrick