and the people of the deserts and towns were illuminated by Allah’s light, and Allah’s proof was established against mankind and jinn, when the one who answered the call, from the line of Maʿadd ibn ʿAdnān, arose. May Allah bless him, his family, his Companions, and those who follow them in righteousness, with blessings pleasing to the King, the Judge, and grant them peace accompanied by His good pleasure.

To proceed:

There is no happiness for Allah’s servants, nor salvation in the Hereafter, except through following His Messenger.

“Whoever obeys Allah and His Messenger, He will admit them to gardens beneath which rivers flow, to abide therein forever. That is the great triumph.”

“And whoever disobeys Allah and His Messenger and transgresses His limits, He will admit him to a Fire in which he will abide forever, and he will have a humiliating punishment.”

Obedience to Allah and His Messenger is the axis around which happiness revolves, and the abiding foundation from which salvation never departs.

Allah created creation to worship Him, as He, the Most High, said:

“I did not create jinn and mankind except to worship Me.”

He commanded them to worship Him through obedience to Him and His Messenger. Thus, nothing constitutes worship unless it is obligatory or recommended in Allah’s religion; anything else is a departure from His path. For this reason, he—may Allah bless him and grant him peace—said:

“Whoever performs a deed that does not conform to our teachings, it is rejected.”

Al-Bukhārī and Muslim recorded it in their Sahīh collections.

He—may Allah bless him and grant him peace—also said in the hadith of al-ʿIrbād ibn Sāriyah, reported by the authors of the Sunan collections and graded authentic by al-Tirmidhī:

“Those of you who live after me will see much disagreement. Therefore, adhere to my sunnah and the sunnah of the upright, rightly guided caliphs after me. Hold fast to it and bite firmly onto it with your molars. Beware of newly introduced matters, for every innovation is misguidance.”

The authentic hadith reported by Muslim and others states that he would say in his sermon:

“The best speech is the speech of Allah, and the best guidance is the guidance of Muhammad. The worst matters are those newly introduced, and every innovation is misguidance.”

Allah has mentioned obedience to the Messenger and following him in approximately forty places in the Quran, such as His words, Most High:

“Whoever obeys the Messenger has indeed obeyed Allah.”

And His words, Most High: