Hezekiah"s1 ,777-foot long tunnel was a noteworthy accomplishment. It brought water from the Gihon spring outside the city wall, under the wall of Jerusalem, and into the city, specifically to the pool of Siloam. This made Jerusalem much more self-sufficient in times of invasion than it would have been otherwise. [1][source]
Hezekiah"s reign was one of the best in Judah"s history because of the king"s humility and dependence on God, evidences of which the writer of Kings provided in abundance. Judah declined from then on, however, because most of the subsequent kings were wicked. Judah fell to the Babylonians exactly100 years after Hezekiah died. The prophet Isaiah ministered during the reigns of Uzziah, Jotham, Ahaz, and Hezekiah ( Isaiah 1:1). Micah ministered during the reigns of Jotham, Ahaz, and Hezekiah ( Micah 1:1). Both eighth-century prophets ministered in the Southern Kingdom. [source][source][source]
"Perhaps Hezekiah"s only serious flaw is his inability to prepare Prayer of Manasseh , his successor, to be like himself. On the other hand, how can anyone guarantee the quality of their children"s life choices?" [2][source]
"Between the death of Hezekiah and the final fall of Jerusalem to the Babylonians there lay precisely a century (687-587). Seldom has a nation experienced so many dramatically sudden reversals of fortune in so relatively short a time. Through the first half of the period a vassal of Assyria, Judah then knew in rapid succession periods of independence and of subjection, first to Egypt then to Babylon, before finally destroying herself in futile rebellion against the latter. So quickly did these phases follow one another that it was possible for one Prayer of Manasseh , as Jeremiah did, to have witnessed them all." [3][source]