John 12:34 The crowd spoke up, “We have heard from the Law that the Messiah will remain forever, so how can you say, ‘The Son of Man must be lifted up’? Who is this ‘Son of Man’?”
35 Then Jesus told them, “You are going to have the light just a little while longer. Walk while you have the light, before darkness overtakes you. Whoever walks in the dark does not know where they are going. 36 Believe in the light while you have the light, so that you may become children of light.” When he had finished speaking, Jesus left and hid himself from them.
When Jesus says he must be “lifted up” (v34), the crowd understands that he is referring to his own death. This does not fit at all with their Messianic expectations of a superhero saviour. But Jesus has not come so much to rule as to reveal. There is now an urgency because he will be with them just a little longer as “light”.
What does Jesus mean? The metaphor of light refers to revelation: God is making himself known through the “light” of Jesus. Light is for revealing the the truth about God (Jn 12:46). The life within Jesus is the light for all mankind (Jn 1:4-5). Jesus is ‘the true light’– the true and objective revelation of God— that gives ‘light’– revelation as understanding/knowledge— to everyone (Jn 1:9). Jesus brought the revelation of God into the world but people preferred darkness (Jn 3:19-21). For completeness, the gospel also notes that John the Baptist gave testimony to Jesus as the true revelation of God (Jn 1:7-8, 5:35).
So Jesus is the light of the world; that is, light for the benefit of the world, so that we may know God truly (Jn 8:12, 9:5). Without this revelation of God people stumble and fall in the dark (Jn 11:9-10).
So John 12 is the climax of Jesus’ public call to Israel to believe. This call depends upon his being the true revelation of God and it is now urgent because soon that ‘light’ will be taken away from them. If they do believe they will take on the character of that revelation (become ‘children of light’) and so provide a point of access for others. If they do not, they will remain in darkness.
Lord Jesus, you are the Light given to the world to truly reveal the Father. Please reveal the Father to me in such a way that I will reflect his character and bring him glory. Amen.