Galatians 3:10

Living under the Mosaic Law did not bring blessing but a curse. The reason is that to obtain God’s blessing under the Law a person had to keep it perfectly, and no one could. Even one failure brought God’s curse. Paul cited Deuteronomy 27:26 that was a passage the legalists would have respected highly because it is in a highly legal section of a highly legal book. He did so to support his argument. The Law is similar to a chain; one must forge every single link securely or it will not support the person who clings to it for salvation (cf. Galatians 5:3; James 2:10).

Paul was not changing the original intention of the passage he quoted (i.e., Deuteronomy 27:26). The whole Law taught that people cannot earn God’s blessing. The blessing that people experience because they do God’s will is not something they earn. God grants it freely in grace. What people earn and deserve is cursing and judgment from God since they cannot obey the Law perfectly (Romans 6:23).