Malachi 3:6
The context
Malachi is framed as a disputation, with the people's questions and God's answers set against each other. The book has just announced a coming messenger, a refiner's fire, and a judgment that will purify the sons of Levi. This short verse states the ground on which the next sentence, about Israel not being consumed, rests.
What it establishes
God's constancy is presented as the reason a failing people still exist. The claim is about covenant faithfulness over time, and it is offered as an explanation for mercy rather than a description of the divine nature.
What it does not establish
It is not a philosophical definition of immutability. The verse speaks of reliability toward a particular people, and using it to settle later debates about divine passibility reads more into the line than it carries.
Short note, first pass, October 2026. Corrections welcome.
Cited in these answers
Part of Scripture, Opened — the exegetical layer behind every citation on this site. Scripture quotations are from the ESV.