What is the ruling on a person who has performed the [obligatory] pilgrimage, and after a period of time, happens to slur Allaah the Almighty in a state of rage? How does that affect his pilgrimage? Moreover, is he considered to have become a disbeliever due to this act?

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

If a person is so riled to the extent that he loses his sanity, he is not held accountable for his actions while in this condition, because the mind is the focal point and cause for religious liability. If it is not sound, accountability, in terms of religion, is suspended.

Consequently, if someone, in a fit of anger, commits an act that nullifies Islam, he or she is not considered an apostate because of that [temporary] lack of mental faculties. Thus, the ruling that applies to the mentally insane, is likewise applicable to him or her.

It is narrated that the Prophet, sallallaahu ‘alayhi wa sallam, pointed out  that three people may be absolved of religious accountability: a sleeping individual until he wakes up, the child until he reaches puberty, and the insane until he recovers. [Ahmad, Abu Daawood, An-Nasaa'i, At-Tirmithi and Ibn Maajah]

On the other hand, if a furious individual does something that nullifies Islamic belief, while he is still conscious and sensible, the rulings of apostasy pertain to him.

If he repents, his [previous] pilgrimage is valid and he is not required to make up for it, according to the sound opinion of Ahmad, further advocated by Imam Ash-Shaafi’i . However, Imam Maalik opined that such a person would have to repeat his pilgrimage, because apostasy voids any good deeds preceding it.