Israel’s reaction to adversity gets a little monotonous (verse 5), and it is easy to say, ‘Why cannot they learn to trust God?’
But are not we often as unbelieving?
Notice how Jesus uses this story (verses 6-9) as a ‘type’ in John 3:14; 15.
What parallels are there in the condition of the afflicted and in the means of salvation in each case?
Why a serpent on the pole? Cf. 2.Cor.5:21.
It is worth tracing Israel’s journey on a map from 20:1 onwards. Notice how circuitous it was.
What evidence is there, as against 20:2, 3 and 21:4, 5, that Israel was learning trust and obedience through discipline?
What discipline? Cf. Deut. 8:2.