Yes we need his help and forgiveness. But God did not become a human and just simply die on the cross, why I explained on the link above (of the post) some of the reasons why can't God become a human. It's not about limiting power of God, it's about things which if God does He doesn't seem to be God anymore. And Allah stated himself on the many verses that He doesn't forget, He doesn't lie, None is like him.... So Allah swt is telling us in the Qur'an about things which does not belong to God, if God becomes in human flesh? that he loses his perfect virtues, bc human don't have perfect virtues. and many other things. You fail to realize that I'm not saying these of my own, i'm telling what the Qur'an is saying that God doesn't lie, forget, none is like Him etc. etc. but I don't know if you are paying attention completely to my posts.
As a creation we are perfect, but remember that we don't have perfect virtues, we go to bathroom which is a disgusting thing etc. etc. cuz i've mentioned them 100 times. bc this world is like this, and in Jannah everything is perfect, we don't get sick, we don't get tired, we don't have to go to bathroom and take out what we ate etc.
We are perfect as a creation , but we make sins, and everyone knows that, but bc Adam made a sin, I'm not responsible for that, He a.s made it himself, and Allah take into account every single person and his/her deeds, or forgives him/her.