Keep the Sabbath day to sanctify it, as the Lord thy God hath commanded thee. This phraseology implies that the Sabbath institute was already well known to the people of Israel; so that this commandment was intended, not to enact a new observance, but to enforce the continuance of an observance which had come down to them from earlier times.
The Sabbath was to be kept by being sanctified. This means that it was to be consecrated to God to be used as he had appointed. The sanctification of any object "always goes back to an act of the Divine will, to Divine election and institution.
In other words, it is always a state in which the creature [or institute] is bound to God by the appointment of God himself, which is expressed by קֹדֶשׁ הִקְדִישׁ קִדֵּשׁ קָדוֹשׁ,". The sanctification of the Sabbath, accordingly, was the consecration of that day to the Lord, to be observed as he had enjoined, that is, as a day of rest from all servile work and ordinary occupations.
Among the Jews, those who were careful to keep this law "rested the Sabbath day according to the commandment'' (Luke 23:56). Not, however, in mere indolence and idle vacancy, unworthy of a man. Not thus could the day be sanctified to the Lord.
Man had to "release his soul and body from all their burdens, with all the professions and pursuits of ordinary life, only in order to gather himself together again in God with greater purity and fewer disturbing elements, and renew in him the might of his own better powers".
In the Sabbath institute, therefore, lies the basis of spiritual worship and pious service in Israel.