Benjamin could give no more perfect illustration of the dependence of all men upon the atoning sacrifice of Christ than that of the sinless child. Even the child without the slightest taint of sin or transgression is subject to the effects of the Fall and has no hope of salvation, independent of the atoning sacrifice of Christ.
To be free from sin is a requisite of salvation but is insufficient for salvation. Salvation is in Christ and him alone. it is the atonement of Christ that makes possible the salvation of the sinless child.