Bukhari

Hadith Commentary:
Musaylimah the Liar claimed prophethood in Yamamah, and many people became his followers.
He used to mislead people by showing them tricks and illusions.
He came to Madinah and requested the Prophet (sallallahu alayhi wa sallam) that if you appoint me as your successor after you, I and my companions will believe in you.
At that time, the Prophet (sallallahu alayhi wa sallam) stated this hadith: “Khilafah (caliphate) is a great matter; I will not even give you a piece of a stick.”
Eventually, Musaylimah left with his companions, and his group greatly increased in the land of Yamamah.
During the caliphate of Abu Bakr as-Siddiq (radi Allahu anhu), he launched a military campaign against him, in which the Muslims finally prevailed, and Wahshi killed him; all his companions were scattered.
In the hadith, the word “amrullah” (the command of Allah) has appeared, and this is the relevance to the chapter.

Hadith Commentary:
1.
Musaylimah the Liar claimed prophethood in the region of Yamamah, and he was an extremely deceitful person. Many people, being influenced by him, became his followers. He came to Madinah Tayyibah with many of his followers and requested the Messenger of Allah (sallallahu alayhi wa sallam) that if you appoint me as your successor (khalifah) after you, I, along with my companions, will believe in you. At that time, the Messenger of Allah (sallallahu alayhi wa sallam) had a date-palm stick in his hand. He (sallallahu alayhi wa sallam) said:
“Caliphate is a great thing; I am not even prepared to give you this piece of stick.”
(Sahih al-Bukhari, Hadith 4373)
Eventually, Musaylimah the Liar took his companions and returned to Yamamah. During the caliphate of Abu Bakr as-Siddiq (radi Allahu anhu), a military expedition was launched against him, in which the Muslims prevailed, and he was killed and sent to Hell by Wahshi (radi Allahu anhu).
(Sahih al-Bukhari, al-Maghazi, Hadith: 3620)
In this hadith, it is mentioned that regarding him, the Messenger of Allah (sallallahu alayhi wa sallam) said:
“You cannot go beyond what Allah has decreed concerning you.”
Imam al-Bukhari (rahimahullah) has established the chapter heading from this statement, meaning that the wretchedness and misery that Allah had decreed for you before your existence, you will not deviate from it in the slightest.
At this point, the “command of Allah” (amrullah) refers to His universal and decreed command (amr kawnī wa qadari), not the legislative and prescriptive command (amr shar‘ī wa taklīfī).
(Sharh Kitab at-Tawhid by al-Ghunayman 2/242)
In reality, Imam al-Bukhari (rahimahullah), through this chapter heading and the presented ahadith, intends to refute the Mu‘tazilah, who claim that the command of Allah, which is expressed by the speech of Allah, is His creation. Although Allah has described Himself with this command and speech in the presented noble verse, this style and manner is, according to them, entirely metaphorical and not based on reality. However, the belief of Ahl al-Sunnah is that the speech of Allah, with which the Divine Essence is described, is uncreated. However, its relation to the creation is originated (hadith), and it is dependent upon the will and intention of Allah.
(‘Umdat al-Qari: 18/856)