Tafsir Ibn Kathir -> Surah Muhammad -> Exposing the Hidden Secret of the Hypocrites Allah says,

﴿أَمْ حَسِبَ الَّذِينَ فِى قُلُوبِهِمْ مَّرَضٌ أَن لَّن يُخْرِجَ اللَّهُ أَضْغَـنَهُمْ ﴾

(Or do those in whose hearts is disease think that Allah would never expose their ill--wills) meaning, do the hypocrites think that Allah will not expose their affair to His believing servant Yes indeed, He will expose their affair and manifest it so that those with insight will be able to understand it. In that regard, Allah revealed Surah Bara'ah (or At-Tawbah), in which He clarified the hypocrites' scandals, and pinpointed their practices that are indicative of their hypocrisy. Because of that, this Surah (Surah Bara'ah) is also called "The Exposer''. Adghan is the plural of Dighn, which means what the souls harbor of envy and hatred toward Islam and its people who support it. Allah then says,

﴿وَلَوْ نَشَآءُ لأَرَيْنَـكَهُمْ فَلَعَرَفْتَهُم بِسِيمَـهُمْ﴾

(Had We so willed, We could have shown them clearly to you, so that you would know them by their marks.) Allah is telling His Messenger , "Had We willed, O Muhammad, We would have shown you the specific individuals who are hypocrites, so that you would plainly know them.'' However, Allah did not do that in regard to all of the hypocrites. He conceals His creation, lets their affairs run according to apparent purity, and leaves the inner secrets to the One Who is well aware of them. Allah then adds,

﴿وَلَتَعْرِفَنَّهُمْ فِى لَحْنِ الْقَوْلِ﴾

(But you will know them by the tone of their speech!) which means, `you will know them by their speech that reveals their intentions.' A person declares his association through the context and meaning of his words -- as the Commander of the faithful `Uthman bin `Affan, may Allah be pleased with him, said, "Never would one conceal a secret but Allah will expose it by the look on his face and the uncontrolled words of his tongue.'' Allah then says,

﴿وَلَنَبْلُوَنَّكُم﴾

(And We will surely try you) meaning, `We will surely test you with commands and prohibitions.'

﴿حَتَّى نَعْلَمَ الْمُجَـهِدِينَ مِنكُمْ وَالصَّـبِرِينَ وَنَبْلُوَ أَخْبَـرَكُمْ﴾

(until We know those who strive among you and the patient, and We will put to a test all your affairs.) There is absolutely no doubt that Allah's knowledge precedes the occurrence of all events. In this Ayah, "until We know'' means `until We know of its occurrence.' This is why Ibn `Abbas said in regard to this and similar texts, "Except so that We may know, means, so that We may see.''

﴿إِنَّ الَّذِينَ كَفَرُواْ وَصَدُّواْ عَن سَبِيلِ اللَّهِ وَشَآقُّواْ الرَّسُولَ مِن بَعْدِ مَا تَبَيَّنَ لَهُمُ الْهُدَى لَن يَضُرُّواْ اللَّهَ شَيْئاً وَسَيُحْبِطُ أَعْمَـلَهُمْ - يأَيُّهَا الَّذِينَ ءَامَنُواْ أَطِيعُواْ اللَّهَ وَأَطِيعُواْ الرَّسُولَ وَلاَ تُبْطِلُواْ أَعْمَـلَكُمْ - إِنَّ الَّذِينَ كَفَرُواْ وَصَدُّواْ عَن سَبِيلِ اللَّهِ ثُمَّ مَاتُواْ وَهُمْ كُفَّارٌ فَلَن يَغْفِرَ اللَّهُ لَهُمْ - فَلاَ تَهِنُواْ وَتَدْعُواْ إِلَى السَّلْمِ وَأَنتُمُ الاٌّعْلَوْنَ وَاللَّهُ مَعَكُمْ وَلَن يَتِرَكُمْ أَعْمَـلَكُمْ ﴾

(32. Verily, those who disbelieve, and hinder from the path of Allah, and oppose the Messenger, after the guidance has been clearly shown to them, they will not harm Allah in the least, but He will make their deeds fruitless,) (33. O you who believe! Obey Allah, and obey the Messenger and invalidate not your deeds.) (34. Verily, those who disbelieved and obstructed others from the path of Allah and then died as disbelievers -- never will Allah not forgive them.) (35. So do not lose heart and beg for peace while you are superior. Allah is with you and He will never deprive you of (the reward of) your deeds.)