This Hadith has been narrated by Hazrat Ali (کرم اللّٰہ وجہہ). In this narration he has described the events around the time of the Holy Prophet’s ﷺ last few days before he passed away from this mortal world. Hazrat Ali RAA has narrated that on the last day when the Holy Prophet ﷺ fell really unwell, he said to Hazrat Ali RAA, “Ali, bring a tray (تھال) in which I write that advice after which my Ummah (community) doesn’t go astray.” In those days paper wasn’t very common. Sometimes people wrote on leather, on leaves of a tree, on bones, and sometimes on clay pans.   

Hazrat Ali (may Allah be pleased with him) says that at that time the Holy Prophet ﷺ was so unwell that I feared that if I went to get something to write on, he may pass away in my absence. That is why I told him that whatever you tell me, I will remember it and write it down later. Hazrat Ali RAA says that his revered head was in my arms. The words he was saying were, “Be mindful of Salah, be mindful of Zakat, be good to the slaves you own, and be steadfast to the witness of “There is no God but Allah, and Muhammad (ﷺ) is His subject and Messenger.” Allah Ta’ala will declare Jahannam (Hell) Haraam for whoever remains steadfast to this testament.”   These were the advices the Holy Prophet ﷺ gave in his last moments of life.  

The real purpose of quoting this Hadith is to highlight those advices the Holy Prophet ﷺ gave at such a crucial time and what he emphasized. It seems like these advice are the essence of the commandments of Deen (religion) that the holy Prophet ﷺ preached his entire life. These are the summary of entire Deen.  

 There is another Hadith which has been narrated by Hazrat Ali (may Allah be pleased with him) in which he said that during the last moments of the Holy Prophet ﷺ when the volume of his voice had become really low, when I put my ear to his mouth these were the words he kept saying till the very last moment;  “Be careful about Salah and be careful about your subordinates.”  

This Hadith tells us that among all the commandments and teachings of Deen the one among Huqooq Allah (rights of Allah) the Holy ﷺ Prophet placed the greatest emphasis on was Salah. In another narration, the words “Salah, Zakah, and rights of subordinates” have been mentioned. This tells us that among all the Rights of Allah the Holy Prophet ﷺ placed the greatest emphasis on two sorts of rights, one physical and one financial, the physical one being Salah, and the financial one being Zakat. And among the Rights of People (Huqooq al-Ibad) he placed the greatest emphasis on rights of one’s slaves, servants and subordinates.   The Holy Prophet ﷺ was worried whether his Ummah will falter in following these commandments of Shariah after him, and that being neglectful of these commandments will lead to Jahannam and wrath of Allah Ta’alah, and that is why he emphasized about following these specific commandments even in his last moments in this mortal world.