Generations cleansed by the Cross

How would Jesus cleanse the whole generations from sin on the Cross of Calvary?

"He is the atoning sacrifice for our sins, and not only for our sins but also for the sins of the whole world". 1John.2:2 (NIV)
This verse just stuck me, it reminded me of my father questioning and enquiring me as well as others by asking, "I would believe that He has cleaned the sins before Him (Romans.3:25), but how could He cleanse the sins that were not yet committed after Him"? I didn't answer that question that time and believed in the Lord's sacrificial death and resurrection and truly believed some day God would give me a strong answer that everyone would accept. Atleast after 15 years of waiting, now I know that I have the answer.

We all know that we (from our our forefather Adam and Eve) are all, were made out of dust, Genesis.2:7, and breathed into us the breath of life, Acts.17:25 by God. After being provided with every need by God, man by listening to satan and going against the will of God, man sinned and brought death (Romans.6:23) onto himself and through him to all the next generations (Romans.5:12). So, God cursed Adam saying, "..Since from it you were taken; for dust you are and to dust you will return", Genesis.3:19 (NIV). And now here lies the key to the question, how would Jesus cleanse the sins of all the next generations after His crucifixion in advance? As we are all made out of the dust through Adam, we all have to return back to dust after our death through Adam. "Then shall the dust return to the earth as it was: and the spirit shall return unto God who gave it". Ecclesiastes.12:7 (KJV).

We all know that Jesus died on the Cross of Calvary. His blood drained from His body through the Crown of thorns (Matthew.27:29, Mark.15:17), through whipping (Luke.23:16, John.19:1) and through crucifixion on the Cross by nails (Matthew.27:35, Mark.15:24, Luke.23:33, John.19:18) made the earth (dust) swampy. As we are all made out of dust and return to dust, that very dust was cleansed by the soaking blood of Jesus. But here some may arise a question that, who ever is born after crucifixion of Jesus Christ is holy? However, each child is born into different faiths even if it's Christianity, they all have to confess and believe, "That if thou shalt confess with thy mouth the Lord Jesus, and shalt believe in thine heart that God hath raised him from the dead, thou shalt be saved. For with the heart man believeth unto righteousness; and with the mouth confession is made unto salvation. For the scripture saith, Whosoever believeth on him shall not be ashamed. For there is no difference between the Jew and the Greek (a christian and a non-christian): for the same Lord over all is rich unto all that call upon him. For whosoever shall call upon the name of the Lord shall be saved." Romans.10:9-13 (KJV).