How do we know that God's work of salvation is true?

The truth of God's work in salvation is affirmed in several Scriptures, particularly in Philippians 1:6, where Paul declares that God initiates the work of salvation and will faithfully perform it until the day of Jesus Christ. This is reinforced by the nature of God, who does not change and whose promises are always fulfilled. His character as a sovereign and faithful God assures us that when He begins a work of grace in a person's heart, He will not abandon it but will persevere to the ultimate completion of that work, leading to glorification.