Why is it not enough for Jesus to be human to be the perfect sacrifice, why must he be God?

Regardless of whether Jesus is God or not, why do some stridently hold to, 'Jesus can only cover sin by His own death as God'? Until Jesus' perfect sacrifice/offering, the law required an animal to remedy the debt of sin each person/Israelite had before God. An animal was killed, blood was spilt to cover the sinner's guilt so they be 'cleansed' and made right with God again. >Your lamb must be an unblemished year-old male, and you may take it from the sheep or the goats. Ex 12:5 Paul explains a lot about Christ's sacrifice being sufficient to cover all sin - by him faithful believers are made free from the debt of sin - past present and future. Naturally, all mankind is covered by this sacrifice except the few that may fall outside for some reason or their own choosing. >For by one offering He has perfected for all time those who are sanctified Heb 10:14 >But now He has appeared once for all at the end of the ages to do away with sin by the sacrifice of himself. Heb 9:26 >we have confidence to enter the holy place *by the blood of Jesus*, 20 by a new and living way which He inaugurated for us through the veil, that is, *through His flesh* 10:19-20 >He *learned obedience* from the things which He suffered. 9 And *having been perfected*, He became the source of eternal salvation for all those who obey Him Heb 5:8 **Jesus is holy and without sin why would this *human only* sacrifice not be enough?** EDIT: I thought it would be assumed that Jesus is holy and sinless *because* his Father is God (as scripture provides). Thus he has no inherited sin, and is not a just a 'good' man. Clearly any man apart from Jesus would not suffice.