How do we know that God does not change?

God's immutability is a significant doctrine in Reformed theology, emphasizing that He is constant and unchanging in His nature and purposes. Malachi 3:6 clearly states, 'For I am the Lord, I change not,' assuring believers that His promises and character are steadfast. Unlike humans, who are influenced by circumstances and emotions, God’s decisions and commitments are eternally consistent. This immutability provides comfort and assurance to Christians, knowing that they can trust in His truth and righteousness throughout all generations.