Gospel Will Not Always Be Available

Tyre, Sidon, and Sodom were ancient cities with a long-standing reputation for wickedness (Genesis 18-19; Ezekiel 27-28). Each was destroyed by God for its evil. The people of Bethsaida, Korazin, and Capernaum saw Jesus first hand, and yet they stubbornly refused to repent of their sins and believe in Him. Jesus said that if some of the wickedest cities in the world had seen Him, they would have repented. Because Bethsaida, Korazin, and Capernaum saw Jesus and didn't believe, they would suffer even greater punishment than would the wicked cities that didn't see Jesus. Similarly, nations and cities with churches on every corner and Bibles in every home will have no excuse on judgment day if they do not repent and believe.

http://www3.telus.net/trbrooks/refusaloffer.htm