Commento su Levitico 16:31

In order to make this point even clearer the Torah wrote concerning this Day of Atonement, שבת שבתון היא לכם, this refers to the uniqueness of this day. A Sabbath day is usually honoured with food and drink, whereas the abstaining from physical indulgences i.e. a צום, fast day, is meant to put us in the good graces of G’d. (Isaiah 58,3) The message here is phrased differently but is the same. The self-denial of the Jew on that day results in the concept of the Sabbath being observed at its highest potential.

שבת שבתון היא, “it is a Sabbath of solemn rest;” the word היא, here is spelled with the letter י, not as frequently elsewhere with the letter ו. On the other hand, the same word in the same context in Parshat Emor, (Leviticus 23,32) is spelled with that letter וBoth words are read in accordance with the way they are spelled. If we want to remember this easily we can try and remember Kings I 17,15: ותאכל הוא והיא, “he and she ate;”

חקת עולם, even at a time when there is no Temple, and hence no sacrificial service, the day of Atonement does not lose its function, and the Sabbath observance, i.e. abstention from work as well as the self-denial consisting of fasting for twenty four hours remains in effect.

לכם, “for you (pl. masc.)” this is a reference to the day of Atonement, which has been sanctified for your sakes. On the other hand, the Sabbath of creation is known simply as שבת לה', “a Sabbath to be devoted to heavenly concerns.”