for an entire period during the prayer and makes many movements, his prayer is invalidated. That is because such movement conflicts with the prayer and alters its form; thus, there is no distinction in this regard between deliberate and inadvertent movement.

The second opinion (1) is that if it is done inadvertently, it does not invalidate the prayer unless it changes the prayer from its proper form. For example, if he forgets and, being hungry, walks over to the food and eats, having forgotten that he is in prayer, then remembers only after he has eaten his fill that he is praying—this is utterly incompatible with the prayer and therefore invalidates it.

But if it does not plainly conflict with the prayer, then the correct view is that it does not invalidate the prayer, because the legal principle is that a person is excused for doing a prohibited act out of ignorance or forgetfulness.

Thus, there are four conditions for an act not belonging to the prayer to invalidate it:

1. It must be extensive.
2. It must not be an act of the prayer itself.
3. It must not be due to necessity.
4. It must be continuous—that is, not scattered or intermittent.

“And no prostration is prescribed for a slight amount of it …”

His statement, “And no prostration is prescribed for a slight amount of it,” means that it is neither obligatory nor recommended, since what is prescribed includes both what is obligatory and what is recommended. The author specifically stated that no prostration is prescribed for a slight amount of such movement because there is a difference of opinion concerning this (2). It is customary for authors, when they explicitly negate something that need not be mentioned, thereby to indicate that there is a difference of opinion