Even though He had performed so many signs in their presence, they did not believe in Him.
John 12:37 In-Context
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.
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.
Even after Jesus had performed so many signs in their presence, they still would not believe in him.
This was to fulfill the word of Isaiah the prophet: “Lord, who has believed our message and to whom has the arm of the Lord been revealed?”
For this reason they could not believe, because, as Isaiah says elsewhere: