Nasai

(1) "Became displeased." Because he did not consider it appropriate to display his own piety, therefore he became displeased at such a question. Or he sensed the danger that if he disclosed it, the questioner or other people would try to emulate him and would fall into hardship. Or he became displeased because in matters of worship—especially fasting—it is prohibited to imitate him, for example: *wisal* (fasting continuously for several days) is his unique characteristic; no other person is permitted to fast for more than one day in the manner of *wisal*. And Allah knows best.

(2) "Are pleased." That is, we are firmly adhering to the religion that Allah, the Exalted, has revealed upon you, therefore forgive our mistake.

Hadith Commentary: Benefits and Issues: (1)
The Interval Between the Construction of the Ka‘bah and Masjid al-Aqsa (Bayt al-Maqdis):
The well-known view regarding the construction of the Ka‘bah and Bayt al-Maqdis is that the Ka‘bah was built by Ibrahim (alayhis salam) and Bayt al-Maqdis was constructed by Sulayman (alayhis salam), and the interval between them amounts to more than a thousand years. However, in the hadith, the interval is mentioned as forty years. The actual matter is that Ibrahim (alayhis salam) and Sulayman (alayhis salam) did not lay the foundations (ta’sis) of these mosques, but rather renewed (tajdid) them (i.e., rebuilt them anew). The original construction was done by the angels before the creation of Adam, and the interval between these constructions and formations is forty (years), or what is meant is the construction by Adam (alayhis salam). Adam (alayhis salam) laid the foundations of both mosques, and the interval between them was forty years. And if the construction by Ibrahim is intended, then it is apparent that just as a place of worship was built for one son, Isma‘il, and his progeny, so too a place of worship would have been constructed for the other son, Ishaq, and his progeny. Therefore, the construction of Bayt al-Maqdis referred to here is that of Ya‘qub ibn Ishaq (alayhis salam), and the interval between the two constructions is forty years.

(2)
The meaning of “wherever the time of prayer comes upon you, pray there” is that you should pray wherever the Shari‘ah has not prohibited prayer. Because, just as purity of clothing and body is necessary for prayer, so too is the cleanliness and purity of the place. The Shari‘ah has prohibited praying in graveyards, bathhouses (hammam), slaughterhouses (the place of slaughter), public roads, and places of filth.

1:
The narrator is in doubt whether he said ((la saama wa laa aftir)) or ((lam yasum wa lam yuftir)) (both have the same meaning). Apparently, this is an informative statement that he did not fast because he opposed the Sunnah, and he did not break the fast because he remained hungry and thirsty, not eating or drinking anything. Another opinion is that this is a supplication against him; by saying this, the Prophet (sallallahu alayhi wa sallam) expressed his disapproval of this action.

Benefits and Issues:
(1)
Fasting for two days and then leaving a day without fasting was not liked by the Prophet (sallallahu alayhi wa sallam) because he (sallallahu alayhi wa sallam) felt that it would be difficult for the average person to adopt this as a regular practice, except for someone who chooses the path of excessiveness, which is not appropriate.

(2)
The other two methods mentioned in the hadith were liked by the Prophet (sallallahu alayhi wa sallam), therefore they are permissible.

(3)
Regarding the third situation, the Noble Prophet (sallallahu alayhi wa sallam) expressed a desire that he would have the strength for it. This means that, due to many other engagements, it was difficult for the Messenger of Allah (sallallahu alayhi wa sallam) to adopt this practice. Therefore, in voluntary acts of worship, a person should adopt such a routine that there is no fear of it interfering with the fulfillment of his other obligations.