“he is my rock, and there is no unrighteousness in him.” - Psalm 92:15
The perfect sacrifice was Jesus Christ. He gave you eternal life when He died on the cross.
The author of Hebrews in chapter 10:11 says, “every priest stands daily at his service, offering repeatedly the same sacrifices, which can never take away sins.” Sacrifice of animals was the primary way of atoning for sin in the Old Testament, but to no avail. The sacrifice was not perfect. Jesus, who kept the whole law, never sinning, never breaking a commandment, was full of righteousness. Should you repent of your sin and believe in Jesus Christ as your savior His righteousness is given to you, and God sees you as His own. Jesus will then become your foundation. He will be your rock, and there is no unrighteousness in him.