:Imam Baqir (PBUH) said

“Whenever Imam Mahdi (PBUH) rises up, he will pat the worshipers on their head and by doing so he will make their minds concentrated and will complete their morality

:Imam Sadiq (PBUH) addressing the Shias said

“You will not perfect your faith until Imam Mahdi (PBUH) rises up, therefore, God would unite 

."your wisdom and the believers will reach their perfection

The source: The book of the “Merciful Government”