Topic: Hebrews 3:7-11
The Hebrews who left Egypt had concrete proof of God's existence and commitment to them. Yet they hardened their hearts against the Lord when the time came for them to claim their promised land. Also, they refused to believe God would give them victory over the people of Canaan. The Hebrews rebelled and resisted Joshua and Caleb's appeals by coming up with justifications for their disbelief.
God responded to the Hebrews with harsh discipline. For 40 years, they wandered in the desert until the adults who defied Him were dead. The Lord considered the lesson about their resistance and discipline very important, so He repeated it in the New Testament. He didn't want people to repeat the Israelites' mistake and harden their hearts against Him.
The way to a hardened heart is gradual. It begins with unbelief, that is hearing but not accepting all or part of God's Word. Instead, a person rebels and chooses to live his life without the Lord. He ignores his conscience and justifies unscriptural behavior. Eventually, his heart becomes so hardened that he's no longer affected by the whisper of God's Spirit.
Stubbornly persisting in choosing our own way is dangerous. The Lord not only disciplines those who rebel against Him, but He also withholds opportunities and blessings. If we take seriously God's warning not to rebel against Him, then we must always be obedient. As our heart grows more tender and receptive, we'll find that we're unable to sin without being convicted by the Spirit.