John 12:37 - They Didn't Believe in Him

John 12:37 - But though he had done so many signs before them, yet they didn't believe in him.

Many times trinitarians and some other will refer to the unbelieving Jews' cause to kill Jesus as proof that Jesus is God; especially as found in John 5:18 and John 8:33.

See my studies:
The Real Reason the Jews Sought to Kill Jesus
The Jewish Leaders’ “Cause” to Kill Jesus

The Jews' outward claim was that Jesus had a demon, and that the works he performed was that of Beelzebub. (Matthew 9:34; 12:24; Mark 3:22; 11:15; John 7:20; 8:48,52; 10:20) Jesus claimed that he performed his miracles by the finger of his God, that is, by means of God's spirit, and that his message was from the God of Israel. (Matthew 12:28; Luke 11:20; John 8:26,40; 10:25,32,37,38) Were not the Jews the actual liars? Should we based our belief on what these Jews presented as their causes to kill him, or in what Jesus himself said?

With all their excuses for killing Jesus, they simply did not wish to acknowledge that Jesus performed his miracles by the hand of the One they claimed as their God (John 8:41,54), and thus they sought one excuse after another to outwardly justify putting him to death. -- Matthew 9:3,11; 12:2,10,14; Mark 3:6; Luke 6:11; 19:47; 20:19; John 5:16,18; 7:25; 8:33.

However, the scriptures show that the real reason they did not wish to believe on Jesus was prideful envy, and also that inwardly they knew that Jesus was the promised heir. Thus, while pride was the cause of their unbelief, there was a degree of willfulness in their unbelief. -- Matthew 12:38; 27:18; Mark 12:7; 15:10; Luke 20:14.