Dear Khalsa ji,

WJKK, WJKF,

I would like to answer this question in one line , because Guru Arjun Dev ji Maharaj has done this for the whole sikh community.
Reference:: Sikh Philosophy Network http://www.sikhphilosophy.net/sikh-sikhi-sikhism/31713-sangrand-and-sikhi.html
Reference:: Sikh Philosophy Network http://www.sikhphilosophy.net/showthread.php?t=31713

"Maha, Divas, murat bhale jis ko nadra kare, Nanak mange darsh daan kripa karo hare"

This is the answer, why sikh sangat cannot under stand

Sekhon