He himself was not the light, but he came to testify to the light.  The true light, which enlightens everyone, was coming into the world.
He was in the world, and the world came into being through him; yet the world did not know him. He came to what was his own, and his own people did not accept him. NRSV

That one (John) definitely was not the light, but was sent to testify to the light. He (the Word) was the true light, that shines on every one by his coming into the world.
He was in the world and the world came into being through him. yet the world did not recognise him. He came to his own homeland, yet his own kin did not receive him. (DNW)

Teach us, good Lord,
to serve thee as thou deservest;
to give and not to count the cost;
to fight and not to heed the wounds;
to toil and not to seek for rest;
to labour and not to ask for any reward,
save that of knowing that we do thy will,
through Jesus Christ our Lord.
Amen

St Ignatius