How do we know the substitutionary atonement is true?

The doctrine of substitutionary atonement is foundational in Reformed theology and is firmly rooted in biblical texts. Mark 10:45 emphasizes that Jesus came to give His life as a ransom for many, indicating that His death was a purposeful sacrifice for the sake of others. This sacrificial act satisfies the justice of God, fulfilling the requirements for sin's penalty on behalf of His elect. Moreover, John 3:16 points to God's love manifesting in giving His Son so that those who believe in Him will not perish but have eternal life. Scripture consistently portrays Christ's sacrifice as central to redemption, affirming the truth of substitutionary atonement across both the Old and New Testaments.