And how good is John's description of John the Baptist's calling! He lived "as a witness to the light, so that any man who heard his testimony might believe in the light." His life was "simply as a personal witness to that light." Personal. Someone who himself has basked in the glow and can speak to its goodness. Someone who, like Moses, has been so intimately involved with the light that now his own face glows for all to see.
The reason I love John's description of John the Baptist's calling is because it's actually our calling too. You and I stand in the direct lineage of Way-preparers like John the Baptist and our greatest pursuit must always be a higher and deeper knowledge - a knowledge of the heart, not just the mind - of that Life which is Light.
Consider King David's understanding of the Life, the Light, the Love of God from Psalm 36:
your faithfulness to the clouds.
Your righteousness is like the mountains of God;
your judgments are like the great deep;
man and beast you save, O Lord.
How precious is your steadfast love, O God!
The children of mankind take refuge in the shadow of your wings.
They feast on the abundance of your house,
and you give them drink from the river of your delights.
For with you is the fountain of life;
in your light do we see light.