The blood of Jesus is what provided us with forgiveness of sins. That sacrifice was so great that it outweighed all our sins. It covered all the sins of the world-past, present, and future.
Most Christians have the idea that the sins they committed before they professed faith in Christ are forgiven at salvation, but any sins that are committed after that time are not forgiven until they repent and ask for forgiveness. This isn't the case.
All our sins: past, present, and future were forgiven through the one offering of Jesus. If God can't forgive future sins, then none of us can be saved because Jesus only died once, nearly 2,000 years ago, before we had committed any sins. All our sins have been forgiven.
The forgiveness of our sins is not the ultimate goal of our salvation. It is just a necessary step. The real goal of salvation is relationship with the Father and sin is a barrier to that relationship. So, it had to be dealt with, and it was, through the blood of our Lord Jesus Christ. But those who stop with the forgiveness of sins and don't go on into eternal life are missing the heart of salvation. Our sins have been forgiven so that we may enter into a personal with the Lord.
It is through the riches of God's grace that we have received forgiveness for our sins. There is nothing we can do to obtain forgiveness except humble ourselves and receive forgiveness as a gift through faith in Christ.
