SHAFAQNA -Imam Sadeq (AS) said: Allah (SWT) has placed a cause for everything and a description for every cause; and a key for every description; and knowledge for every key and for every knowledge an expressive door (gate). Whoever recognizes that door, will know God and whoever denies it, has denied the Almighty. That gate is the Prophet (PBUH) and us (Ahlul Bait) .
 Beharul Anwaar, Vol. 2, Page 90 & Page 168.