Hebrews 10:1-4
10 The law is only a shadow of the good things that are coming–not the realities themselves. For this reason it can never, by the same sacrifices repeated endlessly year after year, make perfect those who draw near to worship. 2 Otherwise, would they not have stopped being offered? For the worshipers would have been cleansed once for all, and would no longer have felt guilty for their sins. 3 But those sacrifices are an annual reminder of sins. 4 It is impossible for the blood of bulls and goats to take away sins.

Here, the writer of Hebrews describes the process of presenting offerings to God for cleansing of sins as being an ineffectual process, never truly getting rid of the sins themselves, but only appeasing everyone’s conscience for a little while. After all, the people themselves didn’t stop sinning after giving an offering, so the process had to be repeated over and over again, whether annually or weekly. And, he notes lastly, “it is impossible for the blood of bulls and goats to take away sins”–which undermines the meaning of the whole sin-offering sentiment anyway.

Yet this is the way sins were “cleansed” for hundreds of years in ancient Israel; it was the only way to even attempt living a pure lifestyle, because the Messiah had not come yet. But none of these sacrifices could make the sinners perfect in God’s eyes–even if they clung to the Law as tightly as they could, they still sinned. This period of time existed to prove that humans alone could not live a completely righteous, sinless life, nor could they atone for their own sins.

Contrast that with Jesus, the Messiah, who came to earth as God in human form, living a sinless life so that He would be a perfect sacrifice. His death on the cross WOULD cleanse all sin once for all those who believe. Instead of having to make “endless” sacrifices for their sins, now people could move on from past sins, starting fresh from the moment they professed faith in Jesus’ ability to save their souls and bring them back into a right relationship with God. Jesus did what the Law and humanity’s own efforts could never do: forge a spiritual bridge between God and humanity again.

Now, it’s important to note that believing Jesus is our personal Savior does not stop us from sinning entirely. But it does (or should) inspire us to lead Christlike lives, and it is the only way to go to Heaven. Because of Jesus and no one else, we have hope for heaven–not because of anything we did, but because God saw fit to give us a way back to Him.