Is a person obligated to declare himself an apostate if he utters a statement of disbelief unknowingly, or holds a belief unknowingly? Is he excused by ignorance, or should he consider himself an apostate? And is reviling time by saying "a strange time" considered an act of disbelief?

The fundamental principle is that whoever's Islam is established with certainty does not exit from it except with certainty. Disbelief is not judged except after fulfilling the conditions and removing the impediments. Ignorance stemming from a lack of clear communication (of the message) is an excuse, but not all ignorance is an excuse. What is known of the religion by necessity is not excused by a claim of ignorance from anyone; so, whoever denies it—and is someone who cannot be ignorant of such a matter—exits the fold of Islam. Haste in declaring someone a disbeliever has severe consequences, and its judgment is for the scholars and judges. Whoever commits an act of disbelief ignorantly is not judged to be a disbeliever until the proof is established against him. As for describing time (ad-dahr) with blame and fault, it is forbidden. However, merely describing or informing (about it) is not forbidden.