"God presented Christ as a sacrifice of atonement, through the shedding of His blood--to be received by faith. He did this to demonstrate His righteousness, because in His forbearance He had left the sins committed beforehand unpunished--"
We need to take a journey back to the Old Testament to understand atonement sacrifices. When God gave Moses the law of the Israel Nation, He instructed Moses to build a portable Tabernacle (they were still traveling to the Promised Land). Only priests chosen by God (the Levites) could enter this Tabernacle. The main purpose for the Tabernacle was for God to be able to dwell among His people. The Israelites pitched their tents all around the Tabernacle tent so that it was in the middle of their campground.
The Israelites knew when God was in the Tabernacle because the Pillar of Cloud or Fire would be over the Tabernacle. Therefore, to be able to enter the Tabernacle, one had to be Holy since it was the dwelling place of the Holy God. The priests would offer sin sacrifices daily. Then once a year, on the day of Atonement, the high priest would enter the Most Holy Place (the actual place God dwelled) and offer an Atonement Sacrifice.
This sacrifice would be for all the sins of the people that had been committed for the year. Only the high priest was allowed to do this. There were many preparations that needed to be performed like washing and cleansing before the high priest could enter the Most Holy Place where God dwelled. Since humans are sinners and God is Holy, He can't be near us. (Exodus 25-30)
This is where Jesus comes in!! He became that Atonement Sacrifice for all of us. He was the sin sacrifice for all the people. However, since Jesus was the Son of God, making Him God, He is infinite. Since Jesus is Eternal and Infinite, His sacrifice can cover the sins of people yet to come, like you and me! That's so amazing because the price of our sins was paid for over 2000 years ago. We will never see that price (death) because Jesus has canceled it for us.
Have you studied the Old Testament so that you can understand the references in the New Testament? I encourage you to go back to Genesis and Exodus because they are so rich with the foundation of God's plan. The entire Bible points to Jesus and I can really understand that now that I have studied parts of the Old Testament.
With His Love,