John 1.8

'He was not that Light, but was sent to bear witness to that Light.'

How easy it is to start thinking that we ourselves are the Light, that somehow we too can do good, that we can save people from their earthly and everlasting perdition, that somehow our kindness, our goodness, can help the unfortunate, taking for ourselves the glory that belongs to God.
Moses made the same mistake when he stood by the Jordan, ready to enter the Promised Land. He began to believe that it was he, and not the Lord, that had taken the Israelites thus far.
Our vanity leads us astray. Sure of our goodness, we do harm, all with the best intentions. We pronounce certain political points of view which originate from our own self-interest and prejudice rather than anything in the Gospel.
I am not the Light that shines in the darkness, and neither are you. For all our efforts we can neither help or save anyone. The best we can hope for is to be God's instrument.
Jesus Christ is the Light who shines in the darkness. Like John the Baptist we are to bear witness to the Light, and to never forget, as Moses did, that all the glory is God's.