Galatians 3:10

For as many as are of the works of the law are under a curse: for it is written, Cursed is every one who continueth not in all things that are written in the book of the law, to do them.

The human impossibility of any man's doing "All the things of the law" rendered every man attempting to do so subject to the curse, here quoted from Deuteronomy 27:26. The Galatians, by fooling around with circumcision and Jewish festival, had inadvertently obligated themselves, under penalty of God's curse, to keep the whole law, every jot and tittle of it, an achievement which only Jesus Christ accomplished.