11 Apr. Moses erects a bronze snake to heal the Israelites
“The Israelites left Mount Hor and went on the road towards the Red Sea, in order to go round the country of Edom. But the people became impatient on the way and grumbled at God and Moses. They said, ‘Why did you bring us out of Egypt to die in this desert? There is no bread and no water, and we hate this terrible food!’”
“So the LORD sent them poisonous snakes; they bit the people, and many of the Israelites died. The people came to Moses and said, ‘We sinned when we grumbled at you and the LORD. Pray that the LORD will take away these snakes.’ So Moses prayed for the people.”
“The LORD said to Moses, ‘Make a bronze snake, and put it on a pole. When anyone who is bitten looks at it, that person will live.’ So Moses made a bronze snake and put it on a pole. Then when a snake bit anyone, that person looked at the bronze snake and lived.”
(Numbers 21:4-9)
After the devastating attack by the king of Arad, the Israelites had turned south from Mount Hor and had retraced their steps towards Ezion-geber and the Red Sea in order to skirt round to the south and east of Edom.
As they crossed the dry southern Negev Desert, many of them were bitten by poisonous snakes. When the people begged Moses to pray that God would get rid of the snakes, the LORD commanded Moses to make a bronze snake on a pole so that those who were bitten could look up at it and be healed by God’s power.
Later, the bronze snake itself (called the 'Nehushtan') became revered in its own right, so God ordered its destruction in order to stop any form of idol worship (see 2 Kings 18:4).
This symbol of a snake twined around a pole is used today as an internationally recognised symbol denoting the availability of medical assistance. The brazen serpent monument on the summit of Mt Nebo commemorates this incident.
The photo (by Jerzy Strzelecki) shows the Bronze Serpent monument on Mt Nebo.
You can read more about Mount Hor @ https://www.thebiblejourney.org/biblejourney2/26-the-journey-continues-from-sinai-to-moab/the-israelites-attempt-to-enter-canaan/