First: Sexual Intercourse: There is consensus among scholars about this as mentioned by Ibn Al-Munthir, Ibn Hazm and Ibn Hubayrah .
Second: Touching the wife or the bondmaid out of desire: However, if this is not done out of desire, one’s I‘tikaaf (seclusion in the mosque) will not be invalidated according to the consensus of the four Imaams that is supported by the Hadeeth of ‘Aa’ishah, may Allah be pleased with her, where it was mentioned that she would comb the hair of the Prophet, , during his I‘tikaaf.
Third: Ejaculation because of touching, continuous looking or masturbation.
Fourth: Menstruation or post-partum bleeding.
Fifth: Losing control over one’s mind because of consuming intoxicants.
Sixth: Apostasy.
Seventh: Interrupting the Intention of I‘tikaaf, not being determined or hesitant about interrupting it: This needs some clarification. One’s I‘tikaaf will be actually invalidated if he interrupts his intention of I‘tikaaf even if he is still in the mosque. However, if one says that he will leave the mosque, Allah willing, after the sunset and then changes his mind, his I‘tikaaf will not be invalidated. Likewise, if one is hesitant whether to go out of the mosque or not, this will not invalidate his I‘tikaaf based on the principle that states that certainty is not removed by doubt. When one is making I‘tikaaf, his I‘tikaaf is a certainty that is not removed except with certainty. Hence, if one says, “I have now interrupted my I‘tikaaf,” his I‘tikaaf will be invalidated even if he is still in the mosque. However, if he says, “I will go out after an hour or two,” and he is determined to do that, but then changes his intention and does not go out, his I‘tikaaf will not be invalidated. The same applies to the case of being hesitant whether to end one’s I‘tikaaf or not.
Eighth: Death: This is supported by the Hadeeth: “When the son of Aadam dies, all his deeds stop except for three things.”
I‘tikaaf is not invalidated by wet dreams or ejaculation because of thinking since Allah The Almighty does not charge a soul with anything beyond its ability. Moreover, despite the seriousness of backbiting and talebearing, they do not invalidate I‘tikaaf, yet they cause the reward of the one committing them to diminish and make him sinful.
Scholars mentioned this principle: I‘tikaaf is invalidated on condition that one invalidates it while knowing, remembering and doing this willingly. However, if he is ignorant, forgetful or is forced, his I‘tikaaf will not be invalidated because it is counted among the actions that a person is required to avoid and one is excused in case he commits it while being ignorant, forgetful or forced unlike the commands that could still be fulfilled.