In antiquity number 7 was considered magical. Today there are many references to this number:
- 7 days in a week;
- 7 mortal sins (Christianity)
- 7 chakra;
- 7 divine rays;
- 7 bodies;
etc.
In numerology, 7x7, which is 49, has an even more profound effect. In Kabala 49 signifies number of steps in a ladder of spiritiual purification that lead to the top, step number 50. Think of step 50 as Judaic Enlightenment. Only Moses reached that level.
In Judaica, ascent on this ladder to Enlightenment is symbolically represented by 49 days of Omer - period between Passover & Shavuot, day when Jews received scroll of tora.
(FYI, "shavuot" in Hebrew means "weeks" - another reference to number 7.)
Christianity moved this period to earlier time, yet number of days was kept the same. It's a period of Lent.
Today I learnt that Buddhism also has such period:
http://www.newsru.com/religy/15jul2010/povorot_print.html In Buddhism this period culminates in holiday dedicated to "Turning of Wheel of Teaching" (of Shakyamuni buddha). Gautama had been silent for 49 days while attaining Enlightenment, and then he broke his silence by teaching the 4 noble truths.
By the way, recall that human body contains total of 49 chakra.
It all comes together...