How do we know the doctrine of interposition is true?

The doctrine of interposition is supported by biblical teachings that show Christ's essential role in salvation, where He bears the wrath of God on behalf of His people. This is evident in the sermon through the example of Melchizedek and the implications found in Scriptures like Psalm 124. The sermon points out that believers owe their salvation to God's gracious act of sending Christ to interpose between us and the wrath of God, affirming this doctrine through both narrative and the theological truths contained in the Bible.