This document contains excerpts from a lesson on understanding the Islamic faith (Al-Islam) given by Ustaz Zhulkeflee Hj Ismail. The lesson discusses the Christian doctrine of original sin, providing background on its origins and development. It explains how original sin is understood to have entered the world through Adam's disobedience and how his fallen nature is passed down. The lesson also cites passages from the Bible used to support this doctrine and presents responses and evidence from an Islamic perspective.