Sara and I were out soulwinning last Thursday, and asked a man the question, "Are you 100% sure that if you were to die today, you would go to Heaven?" and he answered that he was not sure. Well, it turns out that he had accepted Christ as his savior, but believed that he could be further condemned by committing new sins before his death. This led to a long discussion about the permanence of our salvation.
The Bible gives us many assurances of eternal salvation. The most obvious example is in the very definition of our salvation, as given in John 3:16; "For God so loved the world, that he gave his only begotten Son, that whosoever believeth in him should not perish, but have everlasting life." Romans 6:23 states that: "For the wages of sin is death; but the gift of God is eternal life through Jesus Christ our Lord."
Jhn 10:27 My sheep hear my voice, and I know them, and they follow me: