The true light that gives light to everyone was coming into the world.
The sense of the Greek word translated true here is not true as opposed to false, but true in the sense of ideal perfection (Ellicott). Its the difference between the light of a candle compared to the brightness of the noonday sun. John the Baptist’s preaching was like candlelight compared to that of the Lord Jesus, who shone with the full strength of original, uncreated light; light that has no equal.
Daily reading: Jeremiah 17
Bible in one year : Judges 7-8; John 3:19-36