To understand the need for God's salvation, we must first understand the problem that we all face. The Bible teaches us that Adam and Eve committed the first sin of humanity by disobeying God's instructions in the Garden of Eden. Since that point everyone after that has been born into sin. All mankind has been separated from God because of our sins just like Adam and Eve.
Not only does sin separate us form God, but sin will also be punished by God. This is everyone's biggest problem. Romans 3:23 "For all have sinned and fall short of the glory of God." Sin is breaking the law of God and just like the civil law there must be a payment for the law that was broken. The payment that God demands for sins against Him is death. Romans 6:23a "for the wages of sin is death." We will face this punishment for our sin unless there would be someone who would pay the price for our sins.