الَّذِينَ يُؤْمِنُونَ بالغیب وَ يُقِيمُونَ الصَّلاة وَ مِمَّا رَزَقْناهُمْ يُنْفِقُون. [بقره/۳]

Translation:
Righteous are those who believe in the Unseen [the occulted imam], maintain the prayer, and spend out of what we have provided for them [all the gifts by God] (Al-Baqarah, verse 3)

Imam Sadiq (pbuh) stated in interpretation of this verse, “Pious are those who confess and [also] believe in arising of Imam Mahdi (hgr), which is certainly true and the Unseen [in this text] refers to the occulted Imam.

۲۰۱۶/۱۰/۱۶

Al-Burhan Fi Tafsir al-Quran, V.1, P.124

Kamaaluddin, V.1, P.17&18; V.2, P.340