The Bible is very clear about man's need for God. It is clear about the eternal afterlife. It also clearly states that God Himself holds the keys to Heaven and Hell.
The following Scripture verses constitute a sample outline of the Bible's consistent theme: that God offers only through Jesus the remedy for man's sin problem and its eternal consequences.
"righteousness and judgment are the habitation of his throne." (Psalm 97:2)
(see also Leviticus 11:44; I Samuel 2:2; Isaiah 6:3; Isaiah 43:3; Revelation 4:8-11)
"for all have sinned, and come short of the glory of God." (Romans 3:23)
(see also Romans 3:10-12; I John 1:8-10)
"But your iniquities have separated between you and your God, and your sins have hid His face from you" (Isaiah 59:2)
(see also Genesis 2:17; Romans 5:12; Romans 14:12; Ephesians 2:1)
"for the wages of sin is death..." (Romans 6:23a)
(see also John 8:24; Romans 5:12; Romans 8:6-8)
"by the deeds of the law there shall no flesh be justified in His sight" (Romans 3:20)
(see also Galatians 2:16 & 21; Galatians 3:11 & 24)
"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." (John 3:16)
(see also John 3:14-16; Romans 5:6-8 & 17-19; Galatians 1:3,4; Colossians 2:13,14; I Timothy 1:15)
"if thou shalt confess with thy mouth the Lord Jesus, and shalt believe in thine heart that God hath raised Him from the dead, thou shalt be saved." (Romans 10:9)
(see also John 3:36; John 6:38-40; John 10:9-11; John 14:6; Acts 2:21; Acts 4:10-12; Romans 6:23; Romans 8:1,2; Romans 10:9 & 13; Ephesians 2:8,9; I Timothy 2:5; Hebrews 10:11-22; Hebrews 11:6; I John 5:12)