The book "DO NOT HARDEN YOUR HEART" was written by the author understanding how important is it to respond to the Holy Spirit when He speaks to us. This book is based on the Scripture Hebrews 3:7-8 "So as the Holy Spirit says: 'Today, if you hear His voice, do not harden your hearts as when they provoked me, as in the days of trial in the wilderness. Where your fathers tried me by testing me, and saw my works for forty years." This book was written to remind the Christians about the importance of the word today in this verse which is the key word and it point out necessity or importance. The Word of God does not say yesterday or tomorrow. It says today. There are lots of things to be taken care of today but the Word of God says "Today, if you hear His voice, do not harden your heart." If you do not do what the Lord is saying to you today you may end up losing important things in life. God does not want to lose any of His children. It was not in the plan of God for any of His people to go to hell. He is calling His children in different ways but in this verse the Holy Spirit stresses it that today when people hear the Word of God, they must harden their hearts. God is calling everybody with all kinds of problems not to concentrates on their problems but to listen to the Holy Spirit when He speaks to them. It is important to listen to the Holy Spirit and respond. God is prepared to bless us according to His riches in glory. He wants us to have joy. Peace and whole life.