In the story from the Book of Numbers all who looked upon the bonze serpent that Moses lifted up were saved. John, in his Gospel recalled three times when Jesus compared himself to that bronze serpent.
In Chapter Three John quoted Jesus saying that just as Moses lifted up the serpent, so too he must be lifted up so that all who believe might have eternal life.
In Chapter Eight we read how Jesus told his foes, “When you see me lifted up you will know that I Am.
In Chapter Twelve John quoted Jesus as saying, “When I am lifted up I will draw all men to me.”
What is common to those three occasions is that through his life Jesus was haunted by his dreadful fate of being nailed to a cross, then lifted up.