Isaiah 56:2

That keepeth the Sabbath from polluting it - Kimchi has an excellent note here. "The Sabbath is sanctified when it is distinguished in dignity; and separated from other days.

1. As to the body, in meat, drink, and clean clothing.

As to the soul, that it be empty of worldly occupations, and be busily employed in the words of the law and wisdom, and in meditation on the works of the Lord."

The rabbins say, "Jerusalem had never been destroyed, had not the Sabbaths been profaned in it."