I put this out for consideration.
Having been a Sabbath KEEPER for decades (but no longer), I suggest the understanding may be similar for those in Christ (who he was talking to) who may still OBSERVE (1) a Sabbath and cherish the opportunity for time with God and family - brother and sisters in Christ.
To be deprived of this generational observance, because they were 'fleeing', would be an extra burden to bear.
There is no 'command' to keep a Sabbath under the New Covenant, but that does not diminish the opportunity to partake of the benefits long held dear.
- by observe I mean to set the day aside for generally Godly purposes and pursuits, but not to adhere to the sunset to sunset, or many other limitations imposed on the 'holy time that was required under the law.