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.
"You must understand how bad sin is to God. Sin is a personal offense because it is rejection of His authority. Sin belies the holiness of God. When Adam took that one bite of the fruit, it shattered the glass of holiness. He rebelled against the holy God and his eyes were opened to sin. With that one sin, the whole human race and all of creation was plunged into the consequences of it.
That one sin started Genesis 3:15 into motion. One sin made it necessary for the bruising of the Saviour at Calvary. One sin caused hell—one transgression would take all the fury of God against Christ to overcome…They nailed Him to the cross and there is no glamorization of the details as we would do if we had written this. There is no romanticism of the sufferings of the cross…
Our crosses are sanitized and they decorate buildings and baptisteries. Our crosses are often jewelry with diamonds, but theirs were blood stained instruments of torture. None of them would ever glamorize the cross." (Excerpted fromt the sermon, The Bruising of the Woman's Seed -- Pastor V. Mark Smith)