The Origin اصل
Allah the Almighty says in the Holy Quran:
أَلَمْ تَرَ كَيْفَ ضَرَبَ اللَّهُ مَثَلًا كَلِمَةً طَيِّبَةً كَشَجَرَةٍ طَيِّبَةٍ أَصْلُهَا ثَابِتٌ وَفَرْعُهَا فِي السَّمَآءِ
Have you not regarded how Allah has drawn a parable? A good word is like a good tree: it has a fixed origin and its branches are spread out in the sky. 1
The interpretation of this holy verse as Imam Sadiq (peace be upon him) has mentioned is as follows:
Prophet Muhammed and the sacred Imams (peace be upon them) are the truth of the “fixed origin” 2
The meaning of this sentence is that the Prophet Muhammad and the Holy Imams are the root and origin of all the best (goodness) in the universe.
As Imam Sadiq (peace be upon him) has mentioned in another narration:
We (the sacred Imams) are the root and origin of all the best (goodness) in the world, and all the righteousness and virtues are among our branches, so knowledge of Allah (tawhid), reciting prayers, fasting… are all among our branches. 3
We also read in the Ziyarat Jami‘ah Kabirah that When goodness is considered, you are its beginning, origin, branch, essence, center, and end.