21. Take heed to yourselves--literally, "to your souls." MAURER explains, "as ye love your lives"; a phrase used here to give the greater weight to the command.
      sabbath--The non-observance of it was a chief cause of the captivity, the number of years of the latter, seventy, being exactly made to agree with the number of Sabbaths which elapsed during the four hundred ninety years of their possession of Canaan from Saul to their removal (Le 26:34, 35; 2Ch 36:21). On the restoration, therefore, stress was especially laid on Sabbath observance (Ne 13:19).
      Jerusalem--It would have been scandalous anywhere; but in the capital, Jerusalem, it was an open insult to God. Sabbath-hallowing is intended as a symbol of holiness in general (Eze 20:12); therefore much stress is laid on it; the Jews' gross impiety is manifested in their setting God's will at naught, in the case of such an easy and positive command.

JFB.