Shared ground
Hezekiah is interpreting his own near-death crisis after the fact. He does not present the experience as random. He says the Lord both spoke and then did what was spoken (explicit claim). That combination frames the whole episode as something God deliberately addressed, not merely something Hezekiah survived.
Hezekiah also holds together two realities: the ordeal left “bitterness” in his inner life, and yet the outcome is restored life. His future posture is slowed and subdued (“go softly”) because the memory of that bitterness remains (explicit claim). At the same time, he credits God with recovery and continued life (explicit claim).
A final shared emphasis is moral as well as physical: he links deliverance from the “pit of corruption” with God putting his sins “behind” God’s back (explicit claim). Whatever else is going on, Hezekiah understands restored life to include removal of guilt, not only improved health.
Where interpretation differs
Two phrases carry most of the uncertainty.
First, “I shall go softly” can be read as: (1) humility and carefulness because suffering changed him, or (2) lingering weakness and a slowed pace due to lasting effects. Both fit the line that his “soul” still tastes bitterness.
Second, “by these things men live” can mean different “things”: (1) God’s spoken word and acts in this crisis, (2) the hardships and disciplines that came with the crisis, or (3) God’s dealings more broadly (warnings, mercies, corrections). The verse itself does not specify, but it ties “these things” to the continuing “life of my spirit” and to God’s act of recovery.
Why the disagreement exists
The poem uses compressed language and pronouns without naming the referent (“these things”), and it mixes concrete images (recovery from illness) with moral language (sins removed). That makes it possible to emphasize either the physical rescue, the inner transformation, or both.
What this passage clearly contributes
The text contributes a way of interpreting severe suffering that is neither denial nor simplification. Hezekiah calls it “great bitterness,” yet says it turned out “for my peace” (explicit claim). “Peace” here at minimum includes restored wellbeing and wholeness after threat, and it is grounded in God’s love and rescue from death (“pit of corruption”). The passage also tightly links preserved life with forgiveness: God’s saving action includes removing sin from view, not merely extending earthly life (explicit claim).