"For God so loved the world, that He gave His only begotten Son, that whosoever believes in Him should not perish, but have everlasting life." - John 3:16
This is God's plan of salvation for the human race. Our sin separates us from God, but the good news is that Jesus Christ took our sins and paid the penalty in our place, as our substitute. Therefore, sin is no longer an issue in salvation. The issue is whether or not a person will accept this payment by faith in Christ.
"For by grace are you saved through faith, and that not of yourselves, it is the gift of God; not of works, lest any man should boast." (Ephesians 2:8-9) When a person believes that Jesus Christ died for their sins, God gives that person eternal life and it has absolutely nothing to do with a person's good works.
No one can deserve or earn this free gift; this gift is accepted by faith alone in Christ alone.
"These things have I written unto you who believe on the name of the Son of God, that you may know that you have eternal life, and that you may believe on the name of the Son of God." - I John 5:13