What is the grammatical analysis (إعراب) of "anfusakum" (أنفسكم) in the words of Allah the Almighty: "O you who have believed, upon you yourselves" (يا أيها الذين آمنوا عليكم أنفسكم)?

The noble verse states: (O you who have believed, upon you is [the responsibility of] yourselves. No harm will come to you from one who strays if you have been guided.) The word "Ya" is a particle of calling, and "Ayyu" is a connector for calling that which is defined with "Al" (the definite article). "Alaykum" is a verb of command in the sense of "Adhere to" or "Be committed to," composed of a preposition and a genitive case. The meaning of the verse is: Adhere to yourselves and protect yourselves. The context clarifies what is to be preserved, which is adherence to guidance. If they were to fall short in inviting to good, then the straying of others would harm them, because the sin of their straying would be borne by them. It has been narrated that Abu Bakr Al-Siddiq, may Allah be pleased with him, ascended the minbar, praised Allah and extolled Him, then said: O people, you recite this verse: (O you who have believed, upon you is [the responsibility of] yourselves. No harm will come to you from one who strays if you have been guided), and you place it in the wrong context. Indeed, I heard the Messenger of Allah, peace and blessings be upon him, say: "If people see evil and do not change it, Allah is about to encompass them with a punishment from Him."