The conscience before and after conversion: A Biblical Guide
The old sacrifices dealt with outward defilement but left the worshiper's conscience untouched. Hebrews 9:11–14 argues from lesser to greater: Christ's own blood cleanses the conscience, and it does so for a purpose, that we might serve the living God.
Hilasterion: propitiation mercy seat and atonement: A Biblical Guide
The gold cover of the ark, called the mercy seat, gives the Bible its word for atonement. Hebrews 9 shows why the blood sprinkled there year after year pointed to Christ's own blood offered once.