Explanation of the author's statement: "The First Chapter on What is Obligatory upon the Servant in His Religion: What is obligatory upon the servant in his religion is following what Allah said"

The Shaykh : Allah the Exalted "The First Chapter on What is Obligatory upon the Servant in His Religion"
Religion is action; the action for which the doer is sought to be rewarded. Any action for which reward is sought is religion. Allah the Exalted said: The meaning of religion here is the Day of Religion, the Day of Reckoning. And He the Exalted said, regarding religion being action, an example from the Qur'an is His saying: And He said: This is what is intended in this chapter. "In his religion" means his action for which he seeks reward. What is obligatory upon the servant in his religion is following what Allah said and what His Messenger (peace and blessings be upon him) said, based on His saying: Then after that, the Rightly Guided Caliphs. This is why we did not say "and what the Caliphs said," but rather hinted that obedience to the Caliphs is subordinate to obedience to Allah and His Messenger, in accordance with His saying: "What He said, and obey those in authority."
And the Rightly Guided Caliphs, the Guided Ones. "Caliphs" is the plural of "khalifah," and they are those who succeeded the Prophet (peace and blessings be upon him) in authority and guidance. As for authority, it is apparent. Among them are the four: Abu Bakr, 'Umar, 'Uthman, and 'Ali.
As for guidance, anyone who engaged in beneficial knowledge, called to the truth, and acted upon the truth, then these are the successors of the Messenger (may Allah's prayer and peace be upon him), beacons of guidance, successors in guidance.
And his saying: "The Rightly Guided, the Guided Ones" Know that "rashd" (right guidance) is following the path of right guidance by a person acting in accordance with what is right, sound, and successful. And "huda" (guidance) for the "muhdidun" (Guided Ones) is through knowledge; guidance is knowledge of the thing. Thus, these people combined beneficial knowledge and righteous action. The beneficial knowledge is in his saying: "The Guided Ones" and the righteous action is in his saying: "The Rightly Guided".
He said: "After him, from among the Companions and those who followed them in excellence". This is what is obligatory upon us in our religion: to follow what Allah and His Messenger said, and what the Rightly Guided Caliphs after him, from among the Companions and those who followed them, said. This is the methodology of the Salaf. If the methodology of the Salaf is mentioned, this is their methodology: that you follow what these people were upon. There is no doubt that the Companions are the best of generations, as will come if Allah wills. The reasoning is: "And that is because Allah sent Muhammad (peace and blessings be upon him) with clear proofs and guidance." The clear proofs are the distinct verses indicating his prophethood, and guidance is knowledge. Allah the Exalted said: And what follows it? So in the Book is knowledge, and the clear proofs are the verses indicating that these are from the messengers.