One, ancient, family had
An inspiration that there
Was, in reality, only one God.

One, ancient, leader who
Heard a challenging message
That the one God had for him.

One, ancient man, who
Believed the promise
That the one god made to him.

And modern man, what of
Us who think we know it all?
That one god kept the promise - in Christ.

The maker of the starry depths
Is the guardian of my way.
The creator of the heavens and earth
Is my ever-wakeful protector.

When I seek for guidance or help
The spirit of the Lord is mine;
Even in the things of everyday
The Lord guards my footsteps.

It is not the ritual that saves
But the faith the believer holds.
It is not the performance of some event
But the transforming of the mind.

It is the Grace of God that saves
Not the deserving of the righteous.
It is the faith the Spirit stirs
Not the reciting of 'significant' words.

The human brain is very material, yet the thoughts it 'constructs' and the 'identity' it builds are quite immaterial, or in our biblical language 'spiritual'.
In this conversation, with Nicodemus, we see the first example, in John's gospel, of Jesus being content to use the limited language of our ignorance to express something of the deep nature of the divine. This in order that we might have some realistic understanding of his purposes.

Verse 16
This speaks to me on a wider level that the 'traditional' "salvation of the world" concept - excellent though this is. For me this is an extraordinary reinforcement of the Genesis concept "and God saw all that he had made, and it was very good." (1:31) In the words "God so loved the world" we can find the meaning that the whole of the physical Creation, of which we are an integral part, is "good" in God's sight. Thus, as Christians, we must not devalue the 'material' over against the 'spiritual' for God has deliberately made both.