God created man to live a perfect life forever, but because the first man and woman chose to rebel against God, we are now all infected with sin (Romans 5:12, Romans 3:23). Sin is what separates us from God and sin is what has us on the path to eternal destruction.
Because of our sin, we all deserve death (Romans 6:23). Sin not only destroys us physically, but also spiritually. Every sin is ultimately committed against God, who is eternal and infinite (Psalm 51:4). Because of that, the just penalty for our sin is also eternal and infinite (Matthew 25:46; Revelation 20:15).
But God, being rich in mercy, made a way for us to be reconciled to Him. Jesus Christ willingly sacrificed Himself for us and was crucified (John 10:15). Jesus stood in our place, and took the wrath of God upon Himself. His death on the cross was the perfect and complete payment for our sin (I John 2:2).
God has already done all of the work. All you must do is receive, in faith, the salvation He offers (Ephesians 2:8-9). Fully trust in Jesus alone as the perfect and only payment for your sins. Believe in Him, and you will not perish (John 3:16). God is offering you salvation as a gift, all you have to do is accept it. Jesus is the only way of salvation (John 14:6).
