Sorry that your understanding is so limited on this.So be it. There is no point in continuing this conversation as I hold no Calvinist bias in what I might write, and you have an axe to grind/dull.
First of all, a grave image is an idol of a false God- Jesus is not a false God.
Secondly, God told Moses to put that serpent on a pole - it was a symbolic foreshadow of Jesus, as Jesus made clear in the scripture I posted, that just as the serpent was lifted up on a pole, so would Jesus.
The rock Moses struck that water came out of was another OT symbology of Jesus, BTW.