SHAFAQNA – To be on the path of spiritual discovery (Shuhud) requires the spiritual ability of the soul to reach accomplishment (Sharh-e-Sadr; true sense of liberation from all sorts of doubt and hesitation). That is why in Ayah 125 of Surah Al-An’am, Allah (SWT) said: “Those whom Allah (SWT) Willeth to guide; God opens their breast to Islam.” And Musa/Moses (AS) who has gone through this continuous path, and his success is due to Sharh-e-Sadr which he requested from God, as mentioned in Ayahs 25 and 26 of Surah Ta-Ha: “O’ my God, expand me my breast/heart. Ease my task for me.” And Allah (SWT) granted him Sharh-e-Sadr.
If anyone wants to find a way to true Islam must have Sharh-e-Sadr, because the realities and knowledge of the extensive universe, do not fit in a tight/rigid heart, as is narrated from Imam Ali (AS) who said: “The expanded heart (by God) has the ability to witness the extensive knowledge, and until the human being is free (from all sorts of doubt and hesitation), cannot learn absolute/complete (undistorted, unambiguous) knowledge .
 Sireye Payambaran Dar Quran, the Grand Ayatollah Javdi Amoli, Vol. 7, Page 165.