From the beginning of creation to the coming of Jesus, God had been forgiving the sins of human beings. But sin had to be punished. So, God accepted the shedding of the blood of an innocent animal instead of the blood of a sinful human being. That is why people offered animal sacrifices.
But in God’s good time, he sent Jesus Christ to be the ultimate sacrifice for our sins. Jesus Christ lived a sinless and innocent life among us. He is called the “lamb of God”, God’s own provision of a substitute sacrifice for the salvation of all people, not just the Israelites. Therefore, we no longer need to bring any animal sacrifices. Jesus has already been sacrificed for our sins once and for all.