"For God so loved the world that he gave his only Son, that whoever believes in him should not perish but have eternal life."
You have asked first about John 3:16; for clarity, let's add the two subsequent verses as well.
"For God so loved the world that he gave his only Son, that whoever believes in him should not perish but have eternal life. For God sent the Son into the world, not to condemn the world, but that the world might be saved through him. He who believes in him is not condemned; he who does not believe is condemned already, because he has not believed in the name of the only Son of God."
Traditionalists believe that the "Son" referred to is Jesus Christ, and this is one of the passages they use to support their contention that belief in Jesus as the "only-begotten" Son of God is essential for salvation.
Metaphysically we understand the "Son" to be equivalent to the "Word" in John 1:1. It describes the Christ -- the creative energy of divine omnipotence, omniscience and omnipresence that is the Presence of God in each individual. It is the Christ, the Word, the creative empowerment that our divine Source sends into the world – as us – to continue the great creative process.
Each of us is the Christ in potential; Jesus became the Christ in expression, and calls each of us to become the Christ in expression as well, so that we can continue to be about his work of healing, loving, forgiving and empowering, thus bringing into expression the new consciousness that Jesus calls 'the kingdom of heaven.'
This is our work to do, it's our truth to find, believe and express. We must believe this about ourselves – we must allow the example of Jesus to release our own Christ energy – in order to accomplish our spiritual purpose. If we don't we are 'condemned' to continue living in lack and ignorance, waiting vainly for a salvation from without that won't come until we realize the power we have within ourselves – the power that we truly are.
Psalm 139 is too long to copy out here; it is a powerful affirmation of the most basic and essential of the universal spiritual principles on which Unity is based: There is only one Presence and one Power in my life and in the universe – God the Good, Omnipotence. I think the heart of this wonderful psalm lies in verses 7 through 12: "Whither shall I go from thy Spirit? Or whither shall I flee from thy presence? If I ascend to heaven, thou art there! If I make my bed in Sheol, thou art there! If I take the wings of the morning and dwell in the uttermost parts of the sea, even there thy hand shall lead me, and thy right hand shall hold me. If I say, 'Let only darkness cover me, and the light about me be night,' even the darkness is not dark to thee, the night is bright as the day; for darkness is as light with thee."
In other words, there can never be any separation between me and God. No matter where I go, no matter how dark I may make my life, whether I lift myself in consciousness to the realm of Spirit or lower myself to the depths of hell (Sheol), God is with me – loving me, supporting me, and keeping me safe. This is not a distant, angry or judgmental God; this is a God that knows us thoroughly and loves us always – a God with which we are always One.