Philo’s ideal sect, the _Therapeutae_, are wont to assemble as a prelude to their greatest feast at the end of seven weeks, “venerating not only the simple week of seven days but also its multiplied power,”[1586] but the chief festival itself occurs on the fiftieth day, “the most holy and natural of numbers, being compounded of the power of the right-angled triangle, which is the principle of the origination and condition of the whole.”[1587] [Sidenote: Also of four and six.] The numbers four and six, however, yield little to seven and fifty in the matter of perfection. It was the fourth day that God chose for the creation of the heavenly bodies, and He did not need six days for the entire work of creation, but it was fitting that that perfect work should be accomplished in a perfect number of days. Six is the product of the first female number, two, and the first male number, three. Indeed, the first three numbers, one, two, and three, whether added or multiplied, give six.[1588] As for four, there are that many elements and seasons; it is the only number produced by the same number—two—whether added to itself or multiplied by itself; it is the first square and as such the emblem of justice and equality; it also represents the cube or solid, as the number one stands for a point, two for a line, and three for a surface.[1589] Furthermore four is the source of “the all-perfect decade,” since one and two and three and four make ten. At this we begin to suspect, and with considerable justification, as the writings of other devotees of the philosophy of numbers would show, that the number of perfect numbers is legion. We may not, however, follow Philo much farther on this topic. Suffice it to add that he finds the fifth day fitting for the creation of animals possessed of five senses,[1590] while he divides the ten plagues of Egypt into three dealing with the more solid elements, earth and water, and performed by Aaron; three dealing with air and fire which were entrusted to Moses; the seventh was committed to both Aaron and Moses; while the other three God reserved for Himself.[1591] [Sidenote: Spirits of the air.]