Chizkiyahu Destroys the Copper Snake
The copper snake Moshe made to heal the Bnei Yisrael lasted 700 years until people worshipped it, and King Chizkiyahu destroyed what his righteous ancestors had left standing.
The Gemara in Chullin (6b) relates that the copper snake that Moshe Rabbeinu was commanded to form lasted over 700 years. The Torah tells us in Parashas Chukas that while in the Wilderness, the Bnei Yisrael complained about the manna and spoke against Hashem and Moshe Rabbeinu. As a punishment, Hashem sent snakes to bite the offenders. Moshe entreated Hashem to have mercy on His nation, whereupon Hashem told Moshe to fashion a snake. Whoever looked at that copper snake was miraculously cured.
Unfortunately, over 700 years later, in the times of Chizkiyahu, people were worshipping the copper snake and treating it as an idol with powers. Chizkiyahu therefore had it destroyed. R’ Yehuda HaNasi raised an interesting question. Assa and Yehoshafat were both righteous kings. They led national campaigns to eradicate idol worship and destroyed any idols that were discovered. Why didn’t they destroy the copper snake? Didn’t they realize that it was a stumbling block and may eventually be used as an idol?