Salvation is a gift from God that cannot be taken away. When a person is saved, he is always saved. Nothing can separate him from eternal life in Christ and he can live with full assurance of Heaven as his future home.
"The first purpose of the darkness was judgment on the people that put Jesus on the cross. Twelve o’clock to three o’clock is the end of three years of the ministry of light. For three years, Jesus was up and down the villages of Galilee and Judea. You cannot put a number on the miracles Jesus did. John wrote there were so many of them that all the books in the world could not contain all He said and did. So much light for three years—nobody had ever seen God’s light in such a spectacular way. How brightly did the light shine? Jesus was like a city built high on a hill—a light that shone so brightly it was impossible to miss. But the people hated the light. They would not come to the light because each time they did Jesus convicted them of sin. He rebuked them each time. Finally, rather than get rid of sin, they decided to get rid of the irritation by extinguishing the light." (Excerpted from the sermon, "The Darkest Day" -- Pastor V. Mark Smith)