'According to the Law' in the Bible

The sons of Levi who receive the priestly office have a command according to the law to collect a tenth from the people—that is, from their brothers—though they have also descended from Abraham.

For when every command had been proclaimed by Moses to all the people according to the law, he took the blood of calves and goats, along with water, scarlet wool, and hyssop, and sprinkled the scroll itself and all the people,

According to the law almost everything is purified with blood, and without the shedding of blood there is no forgiveness.

After He says above, You did not want or delight in sacrifices and offerings, whole burnt offerings and sin offerings (which are offered according to the law),