Hafiz Muhammad Ameen
(1) "You will not find" — No one can be more just than the Prophet, no matter how just a person may be.
(2) "Shaving the head" — Although shaving the head is permissible and is recommended (mustahabb) during Hajj, to make any permissible thing obligatory, to consider it a legal ruling (shar‘i mas’alah), or to unnecessarily declare it recommended (mustahabb) is absolutely impermissible. Those people will also adopt shaving the head as their distinguishing mark and will consider it obligatory. It can also be said that the Prophet mentioned it only as a sign. He did not censure it, because if someone adopts a permissible thing permanently but does not consider it a legal ruling or superior, then there is no harm. Often, a person adopts a permissible thing permanently for his own convenience, such as someone always wearing a shirt or closed shoes. Clearly, there is no objection in this. And if the act is superior and recommended (mustahabb), then to persist in it is, all the more, recommended, such as the two units (rak‘ahs) of Ishraq prayer, etc.
(3) "The last group" — It is as if the mentality of the Khawarij will remain until the Day of Judgment.
(4) "Masih Dajjal" — That is, the false and deceitful Messiah. Just as we now call any claimant of prophethood a "false prophet." Since he will claim to be the Messiah, and at that time the Jews will accept him as the "Messiah" and follow him. Even now, the Jews are awaiting the coming of the Messiah (although Masih ‘alayhis-salam has already come long ago). That is why he is called "Masih Dajjal." "Dajjal" is a descriptive term, not a name or title. Its meaning is: extremely deceitful, a liar, and a fraud. Thus, these words do not establish his being the Messiah, but rather establish his being a liar, just as calling someone a "false prophet" does not establish his prophethood.
(5) "The worst people" — Because they will kill Muslims. And the killer of Muslims is the worst of the inhabitants of Hell.
Source: Sunan Nasa'i: Translation and Benefits by Shaykh Hafiz Muhammad Amin Hafizullah, Page: 4108