How do we know that God cannot lie?

The assurance that God cannot lie is foundational for the believer's faith. In Hebrews 6:18, it declares that it is impossible for God to lie, underscoring the absolute reliability of His promises. This characteristic directly impacts the believer's hope, as we can trust that what God has spoken will come to pass. Unlike humans, who may be deceitful or unreliable, God's truthfulness is integral to His nature. When He declares that He will save His people, it is a promise founded in His unchangeable character and divine authority.