John 3:14 And as Moses lifted up the serpent in the wilderness, so must the Son of Man be lifted up, 15 that whoever believes in him may have eternal life.
As Moses lifted up the serpent in the wilderness, and everyone who looked on it was saved (from the plague of poisonous snakes) Jesus predicted that he too must be lifted up from the earth (on the cross) and then he would draw all mankind unto himself for salvation.
Artist is William John Heaslip 1898-1970, USA and Canada