Philo Judaeus De Opificio Mundi 128

These things, and more still are said in a philosophical spirit about the number seven, on account of which it has received the highest honours, in the highest nature. And it is honoured by those of the highest reputation among both Greeks and barbarians, who devote themselves to mathematical sciences. It was also greatly honoured by Moses, a man much attached to excellence of all sorts, who described its beauty on the most holy pillars of the law, and wrote it in the hearts of all those who were subject to him, commanding them at the end of each period of six days to keep the seventh holy; abstaining from all other works which are done in the seeking after and providing the means of life, devoting that day to the single object of philosophizing with a view to the improvement of their morals, and the examination of their consciences: for conscience being seated in the soul as a judge, is not afraid to reprove men, sometimes employing pretty vehement threats; at other times by milder admonitions, using threats in regard to matters where men appear to be disobedient, of deliberate purpose, and admonitions when their offences seem involuntary, through want of foresight, in order to prevent their hereafter offending in a similar manner.