Why don’t you read it vey slowly, and in context, since the entire letter to the Galatians was against the errors of going back to the law of Moses, against keeping DAYS and times and seasons, and telling them in chapter 4:21 - 31 that the entire covenant given to Moses on Mount Sinai is BONDAGE.
The passage you like to quote says that the law of Moses was not given until 430 years after Abraham, - when it was given TO Moses - and Romans 5:12-13 states that BECAUSE man had no law during that time period from Adam to Moses, though there was sin in the world, it was NOT held against them i e, not IMPUTED to them, because “where there is NO LAW, there is no imputation of sin”.
Rom 5:12 Therefore, just as sin came into the world through one man, and death through sin, and so death spread to all men because all sinned—
Rom 5:13 for sin indeed was in the world before the law was given, but sin is not counted where there is no law.
First Paul states clearly that the law was not given until 430 years after Abraham, and that the law did not negate the covenant promise to Abraham about being the father of many nations-
and then goes on to say that the law, (given 430 years after Abraham) was given because it was needed - since as Paul wrote elsewhere, without the law, there is no knowledge of what sin IS,( and we know from Romans that man had no law from Adam to Moses, and therefore God didn’t count their sins against them).
Also Jesus didn’t change the ceremonial day of rest, the 4th command ENDED when the covenant it was part of ended, and the entire Decalogue ended with it - in fact it’s CALLED the covenant on two tables of stone, and that covenant ended, being replaced by a better covenant, founded on better promises- and there are no days commanded to keep in the two love commands that superseded the old ten.
Do the math: Decalogue = old covenant on two tables of stone, and old covenant has ended.
Deu 4:13 And he declared unto you his covenant, which he commanded you to perform, even ten commandments; and he wrote them upon two tables of stone.
Deu 9:11 And it came to pass at the end of forty days and forty nights, that the LORD gave me the two tables of stone, even the tables of the covenant.
Heb 8:6 But now hath he obtained a more excellent ministry, by how much also he is the mediator of a better covenant, which was established upon better promises.
Heb 8:13 In that he saith, A new covenant, he hath made the first old. Now that which decayeth and waxeth old is ready to vanish away.
