And as Moses lifted up the serpent in the wilderness, even so must the Son of man be lifted up. John 3:14
When the Israelites sinned against God with their complaining because of their journey from the Red Sea to the land of Edom, God allowed fiery serpents to bite them and many of the people died. Those who lived realized their error and said to Moses that they had sinned by speaking against God and to pray for us that God will take these serpents away. Moses prayed for the people and God told him to make a fiery serpent and set it upon a pole. Everyone who is bitten when he look upon this pole, he shall live.
Jesus was set upon a pole (the Cross) for us to look up and live because the fiery serpent (sin) was killing us.
When we repent of our sins and accept him as our Lord and Savior we have life eternally.
Look up and live!