A person unintentionally blasphemed Allaah The Almighty but he fears Him a lot and wants to repent. What is the ruling concerning him? Is his repentance acceptable?

All perfect praise be to Allaah, The Lord of the worlds. I testify that there is none worthy of worship except Allaah, and that Muhammad, sallallaahu ‘alayhi wa sallam, is His slave and messenger.

 Scholars are unanimous that blaspheming Allaah The Almighty is disbelief and that the person who does this act is a disbeliever and an apostate.  However, the majority of the scholars stated that if such a person repents, his repentance is acceptable. Allaah Says (what means): {Say, "O My servants who have transgressed against themselves [by sinning], do not despair of the mercy of Allaah. Indeed, Allaah forgives all sins. Indeed, it is He who is the Forgiving, the Merciful."} [Quran 39:53] This verse includes the sin you mentioned as long as the person has repented and regretted uttering these words especially that it was unintentional.

You have to follow the commandments of Allaah The Almighty and do a lot of good deeds. Allaah The Almighty Says (what means): {And return [in repentance] to your Lord and submit to Him before the punishment comes upon you; then you will not be helped.} [Quran 39:54]

Allaah Knows best.