“The Pythagoreans called the number seven the vehicle of life, as it contained body and soul. They explained it by saying, that the human body consisted of four principal elements, and that the soul is triple, comprising reason, passion, and desire. The ineffable WORD was considered the Seventh and highest of all, for there are six minor substitutes, each belonging to a degree of initiation. The Jews borrowed their Sabbath from the ancients, who called it Saturn’s day and deemed it unlucky, and not the latter from the Israelites when Christianized.
The people of India, Arabia, Syria, and Egypt observed weeks of seven days; and the Romans learned the hebdomadal method from these foreign countries when they became subject to the Empire. Still, it was not until the fourth century that the Roman kalends, nones, and ides were abandoned, and weeks substituted in their place; and the astronomical names of the days, such as dies Solis (day of the Sun), dies Lunae (days of the Moon), dies Martis (days of Mars); dies Mercurii (day of Mercury), dies Jovis (day of Jupiter, dies Veneris (day of Venus), and dies Saturni (day of Saturn), prove that it was not from the Jews that the week of seven days was adopted. Before we examine this number kabalistically, we propose to analyze it from the standpoint of the Judaico-Christian Sabbath.
When Moses instituted the yom shaba, (Shabbath), the allegory of the Lord God resting from his work of creation on the seventh day was but a cloak, or, as the Sohar expresses it, a screen, to hide the true meaning. The Jews reckoned then, as they do now, their days by number, as, day the first; day the second; and so on; yom ahad; yom sheni; yom shelisho; yom rebis; yom shamishi; yom shishehi; Yom SHABA.
“The Hebrew seven שבע, consisting of three letters, S. B. O., has more than one meaning. First of all, it means age or cycle, Shabang; Sabbath שַׁבָּת can be translated old age, as well as rest, and in the old Coptic, Sabe means wisdom, learning. Modern archeologists have found that as in Hebrew Sab שב also means gray-headed, and that therefore the Saba-day was the day on which the “gray-headed men, or ‘aged fathers’ of a tribe, were in the habit of assembling for councils or sacrifices.”
Thus, the week of six days and the seventh, the Saba or Sapta-day period, is of the highest antiquity. The observance of the lunar festivals in India, shows that that nation held hebdomadal meetings as well. With every new quarter the moon brings changes in the atmosphere, hence certain changes are also produced throughout the whole of our universe, of which the meteorological ones are the most insignificant. On this day of the seventh and most powerful of the prismatic days, the adepts of the “Secret Science” meet as they met thousands of years ago, to become the agents of the occult powers of nature (emanations of the working God), and commune with the invisible worlds.
It is in this observance of the seventh day by the old sages – not as the resting day of the Deity, but because they had penetrated into its occult power, that lies the profound veneration of all the heathen philosophers for the number seven which they term the “venerable”, the sacred number. The Pythagorean Tetraktis, revered by the Platonists, was the square placed below the triangle; the latter, or the Trinity embodying the invisible Monad – the unity, and deemed too sacred to be pronounced, except within the walls of a Sanctuary.”
H. P. Blavatsky
The Mark Of God: Understanding Your "I AM Presence" 