Chapter 27 begins with instructions regarding the altar of sacrifice. It was positioned outside the Holy Place. It was therefore the first thing that was encountered as the worshipper approached God's presence. Before the worshipper could proceed, he most make an offering for his sins. An innocent victim must be offered on the altar. It would be the sinners substitute. Literally, the animal sacrifice took the worshippers place. Without that sacrifice which atones for the worshippers' sins, the worshipper could not approach God.
In John 1:29, John the Baptist said when he saw Jesus coming, "Behold, the Lamb of God, who takes away the sin of the world!" John saw Jesus as the ultimate offering on this altar. It was sufficient to make atonement for the sins of everyone in the world. This Lamb is the substitute for anyone who desires access to God. He took my place.