The proposal showed disregard to the land of Canaan, distrust of the Lord's promise, and unwillingness to encounter the difficulties and dangers of conquering and driving out the inhabitants of that land.
Moses is wroth with them. It will becomes any of God's Israel to sit down unconcerned about the difficult and perilous concerns of their brethren, whether public or personal. He reminds them of the fatal consequences of the unbelief and faint-heartedness of their fathers, when they were, as themselves, just ready to enter Canaan.
If men considered as they ought what would be the end of sin, they would be afraid of the beginning of it.