How do we know God is sovereign in Hezekiah's healing?

The narrative of Hezekiah's healing showcases God's sovereignty in that God's purposes are established and unchangeable. When Isaiah proclaims that Hezekiah will die, it underscores that God had a sovereign plan that would not be altered by human actions. However, through Hezekiah's heartfelt prayer, God reveals that He had always intended to extend Hezekiah's life as part of His divine plan. Additionally, the promise of an heir, Manasseh, who is essential in the lineage of Christ, further demonstrates God's overarching control and purpose in salvation history, confirming that everything unfolds according to His eternal decrees.