How Find Comfort after Infant's Death? (1 Cor. 7:14; 2 Sam 12:23; COD 1:17)

As human beings we have a tendency to be sentimental and make our judgements based upon our own bias. We can think that cute infants are unstained from sin because they are too adorable to be sinful. The harsh truth is that we are all sinners from conception. We are all estranged from God because of Adam's rebellion in Eden. If this is true, then how can we take comfort in the tragedy of infant death or a miscarriage? If infants are sinners before the Lord does that mean they are condemned to hell if they die in infancy? How does the covenant of grace give us rich comfort to console us in the midst of infant death?