Today's text from the ESV Study Bible: Numbers 21-22.
It seems to me that we must stop to dwell on this brazen serpent on a pole, as Jesus Christ himself referred back to it when he was telling Nicodemus how he could obtain eternal life:
"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." (John 3:14-15)
The statue pictured here does a fare job of helping us to understand what is going on here.
Jesus Christ became the curse (the snakes in our story), and bore upon himself the curse of God so that we might look upon the brazen staff (Christ's sacrifice) and be healed (new birth/eternal life).
Take some time to observe this cross. See how the snake is representative of Christ, and the snake's head it tilted to represent death? It seems horrific to compare Christ to the snake, but Christ himself spoke these words, and there is infinitely precious understandings here.
To more fully understand, here is Dr. John Piper explaining in video, or text.
I highly recommend you find time to listen, and understand the "type of Christ" used here by Messiah. Once you understand, then perhaps you, like me, will be unable to gaze upon this scene without a deep stirring in your soul.