In the same Jesus and in relationship of faith and love in Him. Jesus had to atone by blood because there was no faith in Him. If they had faith, the curse would not have been invoked and the law requirement for blood would be suspended. That being said, however, and in view of the irrevocable fact of Israel's faithlessness in Christ Jesus, it is the shed blood of Christ that effected atonement for our sins. The basis of forgiveness past and present is the shed blood of Christ.
Blood makes atonement.
But neither is it saying that blood is the sole agent of atonement. The blood of Jesus became the required agent to atonement because Israel had no faith. Atonement and forgiveness of the Son must be by blood in the Old Testament. There were peace offerings and thanks offerings which consisted of fruits of the field, but a sin offering must be made through the blood of the sacrificial animal. Adam sinned in Eden, Eve was deceived.