Verse 41 notes that God straitened the Israelites with his rod. To straiten means to restrict their freedom, to subject them to distress, or in other words, to chasten them. The chastening or disciplining was done by sending “fiery flying serpents” among them. Upon being bitten by the serpents, all they had to do to be healed was look to the serpent Moses raised up on a pole (a type or symbol of Christ, who was also raised up; see John 3:14; Helaman 8:14–15). Because the way to be healed was so simple, many ignored it and would not look and live. Alma, while teaching about Moses’ testimony of the Son of God, gave the best explanation of why many would not look:
“Behold a type was raised up in the wilderness, that whosoever would look upon it might live. And many did look and live.
“But few understood the meaning of those things, and this because of the hardness of their hearts. But there were many who were so hardened that they would not look, therefore they perished. Now the reason they would not look is because they did not believe that it would heal them” (Alma 33:19–20; see also commentary at Alma 33:19–20).
When people are living in sin, they harden their hearts and complain and condemn and criticize true, honest leaders and even God.