The LORD sent many prophets to Manasseh to speak the word of the LORD to him, to warn him to repent of his wickedness, but the king refused to listen. He persecuted the prophets, and had Isaiah cruelly sawn in two (Heb 11:37), and filled Jerusalem with innocent blood, until there were no prophets left in the land. This is why King Josiah had to search diligently for a prophet to inquire of when he heard the Book of the Law for the first time — all of the prophets had been killed.
It was Esarhaddon, king of Assyria, the same who succeeded his father Sennacherib when his brothers killed him, that took Manasseh captive to his palace in Babylon in 677 bc.
For the LORD takes pleasure in His people;
He will beautify the humble with salvation. Psa 149:4
For thus says the High and Lofty One
Who inhabits eternity, whose name is Holy:
“I dwell in the high and holy place,
With him who has a contrite and humble spirit,
To revive the spirit of the humble,
And to revive the heart of the contrite ones.” Isa 57:15
We have read many proofs throughout the history of the Old Testament that reveals the God of the Old Testament is the God of forgiveness, mercy, and grace, not a God of wrath, vengeance, judgment, and anger. His restoration of Manasseh, after Manasseh had sinned so greatly, more than any of the other kings of Judah, is further proof.
The long reign of Manasseh and his son was so full of neglect of the LORD and all His service, that even the priests who served during the reign of Josiah had never even seen the Book of the Law. When they found it and read it to Josiah, they themselves were hearing it also for the first time.
It reminds me of Martin Luther, a German monk who was part of the Augustine order during the 1500s. The word of God was so neglected, that after he had been a monk for a number of years already, he found a Bible in the back of the university library, thick with dust. It was the first Bible he had ever seen in his life, as well as any of the other monks in his order. Reading it set a match to a fuse of revival, called the Reformation, just as Josiah reading the Book of the Law for the first time, set a match to a fuse of revival.
Christians today are reading the Book of the Law, many for the first time, with a heart attitude of obedience as the LORD reveals the written Torah to Ephraim and the Living Torah to Judah. This match set to the fuse of revival, I believe, will dwarf every other revival in history, before the return of the Lord Jesus Christ!!