"In him appeared life and this life was the light of mankind. The light still shines in the darkness and the darkness has never put it out. A man called John [the Baptist] was sent by God as a witness to the light, so that any man who heard his testimony might believe in the light. This man was not himself the light: he was sent simply as a personal witness to that light. That was the true light which shines upon every man as he comes into the world." John 1:5-9
As we read through this, the "light section" of John's famous prologue, we must not miss its all-important opening statement: "In him appeared life and this life was the light of mankind." The "light," which can sound so mystical and nebulous, is none other than the actual life of the Word, Jesus. Yes, as the One who was Creator-God from the beginning. But also as we've come to know Him, the One who walked and talked and lived - "the visible expression of the invisible God." The "light" of God is indivisible from the "life" of Jesus; they are one and the same.
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 steadfast love, O Lord, extends to the heavens,
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.
As intimately as David knew the Light, we must know the Light. As recklessly as John the Baptist gave witness to the Light, so must we. It is Jesus Himself, by the power of the Holy Spirit, who gives us knowledge of His Life and Light, and then gives courage to proclaim Him. Rest in Him; learn from Him; then go!