Explanation of the words of Imam al-Nawawi (may Allah have mercy on him) regarding what he quoted: "

The Shaykh : In the name of Allah, the Most Gracious, the Most Merciful.
The author (may Allah have mercy on him) stated, in what he quoted from Abu Umamah al-Bahili (may Allah be pleased with him), who said: The sermons of the Prophet (peace and blessings be upon him) were of two types: regular and occasional. As for the regular ones, they are his sermons on Fridays and during the festivals, for he (peace and blessings be upon him) used to preach to the people every Friday and every festival. The scholars (may Allah have mercy on them) differed regarding the sermon for the eclipse prayer: is it regular or occasional? The reason for their disagreement is that an eclipse did not occur during the time of the Prophet (peace and blessings be upon him) except once. When he prayed, he stood up and preached to the people (peace and blessings be upon him). Some scholars held that it is among the regular sermons, stating that the original ruling is that whatever the Prophet (peace and blessings be upon him) legislated is established and stable. Since the eclipse did not occur a second time, the Prophet (peace and blessings be upon him) did not omit the sermon, so we say it is among the regular sermons.
And some scholars said, rather, it is among the occasional sermons, which are delivered if there is a cause for them, and if not, they are not delivered. However, the closer view is that it is among the regular sermons, and that it is recommended (sunnah) for a person, when he prays the eclipse prayer, to stand up and preach to the people, reminding them and warning them, as the Prophet (peace and blessings be upon him) did.
As for the occasional sermons, they are those delivered when there is a need for them, such as his sermon (peace and blessings be upon him) when the people of Barirah made a condition. She was a slave woman that Aisha (may Allah be pleased with her) had purchased, and her people made the condition that the clientage (wala') would belong to them. But Aisha (may Allah be pleased with her) did not accept this, so she informed the Prophet (peace and blessings be upon him), and he said: Then he stood up and preached to the people, informing them that clientage belongs to the one who frees the slave.
And likewise his sermon when Usamah ibn Zayd (may Allah be pleased with him) interceded for the woman from the Khazraj tribe who used to borrow goods and then deny it. The Prophet (peace and blessings be upon him) ordered that her hand be cut off. This matter troubled the Quraysh, so they sought someone to intercede for her to the Messenger of Allah (peace and blessings be upon him). They asked Zayd ibn Thabit, and they asked Usamah ibn Zayd (may Allah be pleased with him) to intercede, and he did. But the Prophet (peace and blessings be upon him) said to him: Then he stood up and preached to the people, informing them that what destroyed those before us was
During the Farewell Pilgrimage, the Prophet (peace and blessings be upon him) preached on the Day of 'Arafah and on the Day of Sacrifice, admonishing and reminding the people. This is one of the regular sermons, and it is recommended (sunnah) for the leader of the pilgrims to preach to the people as the Prophet (peace and blessings be upon him) did. Among the things he mentioned in his sermon in the Farewell Hadith was that he said: This is like His saying, the Exalted: So the Prophet (peace and blessings be upon him) ordered all the people to fear their Lord who created them, provided them with His blessings, and prepared them to accept His messages. He ordered them to fear Allah. Meaning: the month of Ramadan. Meaning: give it to its rightful recipients and do not be stingy with it. Meaning: those whom Allah has made rulers over you. This includes the rulers of regions and countries, and it includes the general ruler of the entire state. It is obligatory for the subjects to obey them in other than disobedience to Allah. As for disobedience to Allah, it is not permissible to obey them even if they order it, for the obedience of the created does not take precedence over the obedience of the Creator, Glorified and Exalted is He. For this reason, Allah, the Exalted, said: He linked the obedience of the rulers to the obedience of Allah and His Messenger, and this indicates that it is subordinate, for the linked item is subordinate to the item it is linked to, not independent. For this reason, you find that Allah, Glorified and Exalted, said: He used the verb to make it clear that the obedience of the Prophet (peace and blessings be upon him) is independent obedience, meaning his obedience is obligatory in itself, just as the obedience of Allah is obligatory. And with this, his obedience is part of the obedience of Allah, for the Prophet (peace and blessings be upon him) does not command except what pleases Allah. As for the other rulers, they may command what does not please Allah. For this reason, their obedience was made subordinate to the obedience of Allah and His Messenger. It is not permissible for a person to disobey the rulers in other than disobedience to Allah and say, “This is not religion,” because some ignorant people, when the rulers establish systems that do not contradict the Shari'ah, say, “No, I am not obligated to carry out these systems because they are not by the Shari'ah; they are not found in the Book of Allah or in the Sunnah of His Messenger.” This is due to their ignorance. Rather, we say that complying with these systems is found in the Book of Allah and in the Sunnah of the Messenger (peace and blessings be upon him). Allah, the Exalted, said: And the Prophet (peace and blessings be upon him) said in many hadiths, ordering the obedience of the rulers, including this hadith. So the obedience of the rulers in what they organize that does not contradict the command of Allah and His Messenger, which Allah and His Messenger have commanded, is required. Even if we did not obey the rulers except in what Allah and His Messenger have commanded, there would be no benefit in the command to obey them, for the obedience of Allah and His Messenger is commanded whether the rulers command it or not. These matters that the Prophet (peace and blessings be upon him) advised in the Farewell Pilgrimage—fearing Allah, the five prayers, zakah, fasting, and obeying the rulers—are among the important matters that a person must pay attention to and comply with the command of the Messenger of Allah (peace and blessings be upon him) in them. And Allah knows best.