First matter: The Knowledge obligatory upon us to know

﷽

What is this knowledge obligatory upon us to know and why did the author particularised these 3 matters?

This knowledge obligatory upon us to know covers 3 matters - knowing Allāh, knowing His Prophet ﷺ and knowing Dīn Al-Islām with proofs and evidences. The author particularised these matters as they're the fundamentals of Dīn without which Islām cannot be established and these are the matters about which a person will be asked in the grave. It comprises the whole of the Dīn and should be given great attention for their tremendous benefits. It's the foundation and perfection of one's Islām.

Knowledge and awareness of Allāh by heart 

This necessitates accepting His Commands and yielding to what Allāh, the Most High Demands and to apply Sharī'ah which Prophet Muhammad  ﷺ brought.

How Does a person really Know and be aware about Allāh?

By contemplating the legislated signs and revealations in the Book of Allāh and in the Sunnah of His Messenger ﷺ. Also by contemplating on the universal signs meaning the creations. If a person ponders upon these signs his knowledge will increase concerning his Creator, the One Who he worships, Allāh.

Adh-Dhariyat 51:20-21

وَفِى ٱلْأَرْضِ ءَايَٰتٌ لِّلْمُوقِنِينَ 

And on the earth are signs for those who have Faith with certainty.

وَفِىٓ أَنفُسِكُمْۚ أَفَلَا تُبْصِرُونَ 

And also in your ownselves. Will you not then see?

Knowing of His Messenger Muḥammad ﷺ

This is an obligation on every legally responsible person and one of the fundamental matters of deen as he was the one who conveyed from Allāh, the Most High. This requires accepting what he brought from Allāh, the Most High from Guidance and True Religion, believing in what he conveyed and complying with his commands and to abstain from prohibitions which he made clear as well as applying his Sharī'ah.

An-Nisa' 4:65

فَلَا وَرَبِّكَ لَا يُؤْمِنُونَ حَتَّىٰ يُحَكِّمُوكَ فِيمَا شَجَرَ بَيْنَهُمْ ثُمَّ لَا يَجِدُوا۟ فِىٓ أَنفُسِهِمْ حَرَجًا مِّمَّا قَضَيْتَ وَيُسَلِّمُوا۟ تَسْلِيمًا 

But no, by your Lord, they can have no Faith, until they make you (O Muhammad صلى الله عليه وسلم) judge in all disputes between them, and find in themselves no resistance against your decisions, and accept (them) with full submission.

An-Nur 24:51

إِنَّمَا كَانَ قَوْلَ ٱلْمُؤْمِنِينَ إِذَا دُعُوٓا۟ إِلَى ٱللَّهِ وَرَسُولِهِۦ لِيَحْكُمَ بَيْنَهُمْ أَن يَقُولُوا۟ سَمِعْنَا وَأَطَعْنَاۚ وَأُو۟لَٰٓئِكَ هُمُ ٱلْمُفْلِحُونَ 

The only saying of the faithful believers, when they are called to Allâh (His Words, the Qur’ân) and His Messenger (صلى الله عليه وسلم), to judge between them, is that they say: "We hear and we obey." And such are the successful (who will live forever in Paradise).

An-Nur 24:63

لَّا تَجْعَلُوا۟ دُعَآءَ ٱلرَّسُولِ بَيْنَكُمْ كَدُعَآءِ بَعْضِكُم بَعْضًاۚ قَدْ يَعْلَمُ ٱللَّهُ ٱلَّذِينَ يَتَسَلَّلُونَ مِنكُمْ لِوَاذًاۚ فَلْيَحْذَرِ ٱلَّذِينَ يُخَالِفُونَ عَنْ أَمْرِهِۦٓ أَن تُصِيبَهُمْ فِتْنَةٌ أَوْ يُصِيبَهُمْ عَذَابٌ أَلِيمٌ 

Make not the calling of the Messenger (Muhammad صلى الله عليه وسلم) among you as your calling one of another. Allâh knows those of you who slip away under shelter (of some excuse without taking the permission to leave, from the Messenger (صلى الله عليه وسلم). And let those who oppose the Messenger’s (Muhammad صلى الله عليه وسلم) commandment (i.e. his Sunnah - legal ways, orders, acts of worship, statements) (among the sects) beware, lest some Fitnah (disbelief, trials, afflictions, earthquakes, killing, overpowered by a tyrant) should befall them or a painful torment be inflicted on them.

Imaam Aḥmad said concerning it - "Do you know what the Fitnah is? The Fitnah is shirk since if he rejects anything from his (Muḥammad's) sayings, then some form of heresy may be cast into his heart and cause him to be destroyed."

Knowledge of Deen Al-Islām 

Islaam has 2 meanings, a broader and general meaning and a particular one.

In general it means worshipping Allāh, the Most High in the way He prescribed through the Messengers He Sent. There are many ʾĀyāt which show that the previous revealed laws were all submission (Islām) to Allāh.

Al-Baqarah 2:128

رَبَّنَا وَٱجْعَلْنَا مُسْلِمَيْنِ لَكَ وَمِن ذُرِّيَّتِنَآ أُمَّةً مُّسْلِمَةً لَّكَ وَأَرِنَا مَنَاسِكَنَا  

Our Lord! And make us submissive unto You and of our offspring a nation submissive unto You, and show us our Manâsik

Shaykh Ibn Taymiyyah mentions that Islaam in the general sense means worshipping Allāh, the Most High Alone and that this is the deen of the Prophets. Islaam is not only particular to this Ummah rather it's general.¹

In the particular sense it means the deen which Allāh Had entrusted Prophet ﷺ with and concluded with it all the previous religions and made it the last and only one which will be accepted by Him.

Aal-e-Imran 3:85

وَمَن يَبْتَغِ غَيْرَ ٱلْإِسْلَٰمِ دِينًا فَلَن يُقْبَلَ مِنْهُ وَهُوَ فِى ٱلْءَاخِرَةِ مِنَ ٱلْخَٰسِرِينَ 

And whoever seeks a religion other than Islâm, it will never be accepted of him, and in the Hereafter he will be one of the losers.

Al-Ma'idah 5:3

 ٱلْيَوْمَ أَكْمَلْتُ لَكُمْ دِينَكُمْ وَأَتْمَمْتُ عَلَيْكُمْ نِعْمَتِى وَرَضِيتُ لَكُمُ ٱلْإِسْلَٰمَ دِينًاۚ 

This day, those who disbelieved have given up all hope of your religion; so fear them not, but fear Me. This day, I have perfected your religion for you, completed My Favour upon you, and have chosen for you Islâm as your religion.

Allāh chose this religion for this Ummah. In this sense it's particular.

What's the meaning of evidence?

It means that which leads to what is sought. Proofs for this matter are both textual (affirmed by wahy) and intellectual (established through observation and consideration) Allāh frequently mentions this kind of proofs in many ʾĀyāt when He tells about His signs are such and such through which intellectual proofs are quoted.

Prophet Muḥammad was the last Prophet and Messenger of Allāh. ²Textual proofs for this is in many Sayings of Allāh, the Most High. As for intellectual proofs, it is through observing and examining the clear signs which he came with, Greatest of these signs is the Book of Allāh in addition to the miracles that occured through him and the informations he gave about hidden and unseen which could only be known through wahy.

----------------           

1. [5:44], [10:84], [2:133]

2. [Al Fath:29], [Al Imraan: 144]