I happened to go for a wedding a few days ago. As we knew during Indian weddings, we have 7 rounds (which we call fere or Saptapadi) around the fire and then bride and groom ties a knot for lifetime. I was wondering why do we have 7 feres and not 6 or 8... Then I realized, there are many things which are 7.... wanna check? Lets start from the wedding rounds itself.
1. Saptapadi in weddings.
Initially I used to think as normally people say there are 7 human births a person can have. So each round might be a replica of each birth. But when I asked my grandpa, he said, with each round a couple makes a vow to establish a happy married life. These includes - providing proper food, being strong and complement to one another, being blessed with prosperity, being eternally happy, being blessed with children, living in perfect harmony and finally being always the best of friends.
2. Seven days in a week
Have you ever wondered why there are seven days in a week? There were atleast 9 planets identified when the days, weeks and years into place, then why not 9 days in week, why 7? It may be due to the association of the seven celestial beings (the visible planets plus the Sun and the Moon) with deities in the minds of humans from probably an early stage in the development of intelligence up to the time of the advent of modern science. As we all know they include Sun, moon, Mars, Mercury, Jupiter, Venus and Saturn
3. Seven wonders of the world
The number seven was chosen for this because the Greeks believed it to be the representation of perfection and plenty. However it still continues and now we have different sets of wonders but in number 7 :) like 7 wonders of ancient world, 7 wonders of medieval world, 7 wonders of modern world and etc. etc.
4. Seven colors in a rainbow.
Scientifically, there are many colours in a rainbow, almost infinite if you want to look very very closely. However we only have specific common words for 7 of them, and thus it is commonly known that a rainbow has the 7 colours red, orange, yellow, green, blue, indigo, violet. All the rest we dont see because they are too far away. Again why there are 7 common words for colors is again a mistery...
5. 7 Sur in music (Saptasur)
Indian Music has Saptak Swaras octats (sa re ga ma pa dha ni) which are basics of music, using which hundreds of ragas are composed. The seven notes of the scale (swaras), in Indian music are named shadja, rishabh, gandhar, madhyam, pancham, dhaivat and nishad, usually shortened to Sa, Re, Ga, Ma, Pa, Dha, and Ni and written S, R, G, M, P, D, N. Collectively these notes are known as the sargam (the word is an acronym of the consonants of the first four swaras)
6. Seven deadly sins
Wrath (Anger), Greed (a sin of excess), Sloth (neglecting what God has spoken, and being physically and emotionally inactive), Pride, Lust, Envy and gluttony (over-indulgence) are supposed to be seven deadly sins in the world.
7. Seven spirits of god
As per the old mythes there are seven spirits of god, which include the Spirit of the Lord; the Spirit of wisdom; the Spirit of understanding; the Spirit of counsel; the Spirit of might; the Spirit of knowledge and the Spirit of the fear of the LORD.
Also, as per Hinduism, there are seven worlds in the universe, seven seas in the world and seven Rishies (seven gurus) called sapta rishis. The sapta rishis include Bhrigu, Atri, Angirasa, Vasishta, Pulastya, Pulalaha and Kratu. There are seven virtues as per the catholic history including faith, hope, love, patience, kindness, courage and justice. According to Arthur M. Young there are seven levels of evolution. According to Charles Muses there is a seven-dimensional Q-universe which is the master control center of our 3-d universe.There are seven step pyramids in Mexico, seven step ziggurats of Mesopotamia. And the mystery of number Seven continues :)