The first is when prayers are combined.

The second is in a state of extreme fear, in which one is unable to perform the prayer in any manner whatsoever, as mentioned previously.

May the prayer be delayed because of work, if a person is unable to perform it within its prescribed time and therefore puts it off?

The answer is that if this is due to necessity—such as extinguishing a fire or rescuing someone from drowning—then the apparent ruling is that it is permissible. If it is not due to necessity, it is not permissible.

Whoever denies that it is obligatory has disbelieved, …

His statement, “Whoever denies that it is obligatory has disbelieved,” means: whoever denies the obligation of the prayer whose obligation is established by consensus—namely, the five daily prayers and the Friday prayer—is a disbeliever, because he has rejected Allah, His Messenger, and the definitive consensus of the Muslims. This applies even if he denies its obligation while still performing it; likewise, if he denies the obligation of any part of it, or even denies the obligation of a single unit of prayer, he has disbelieved.

Likewise, if he denies the obligation of just one essential pillar, he has disbelieved, provided that it is a matter agreed upon by consensus. The scholars excepted from this the one who has only recently entered Islam after disbelief and denies its obligation: he is not deemed a disbeliever (1). Rather, the truth is to be explained to him; then, if the truth is presented to him in a clear manner and he still denies it, he has disbelieved. This issue that the scholars have excepted shows that there is no difference between definitive matters of religion and matters based on probable evidence with regard to a person being excused for ignorance. This matter—namely, being excused because of ignorance—is important and requires careful verification, lest we declare disbelieving one whose disbelief is not established by evidence.