Tafsir Ibn Kathir -> Surah At-Taubah -> Allah encourages His Prophet against hypocrites,

﴿لَقَدِ ابْتَغَوُاْ الْفِتْنَةَ مِن قَبْلُ وَقَلَّبُواْ لَكَ الأُمُورَ﴾

(Verily, they had plotted sedition before, and had upset matters for you,) `For a long time,' Allah says, hypocrites thought and plotted against you and your Companions, as well as, failing and attempting to extinguish your religion.' This occurred soon after the Prophet migrated to Al-Madinah, when pagan Arabs joined force and the Jews and hypocrites of Al-Madinah waged war against the Messenger . When Allah gave victory to the Prophet in Badr and raised high his word, `Abdullah bin Ubayy and his fellows said, "This (Islam) is a matter that has prevailed.'' They embraced Islam outwardly, and whenever Allah elevated Islam and its people in might, hypocrites increased in rage and disappointment,

﴿حَتَّى جَآءَ الْحَقُّ وَظَهَرَ أَمْرُ اللَّهِ وَهُمْ كَـرِهُونَ﴾

(until the truth (victory) came and the decree of Allah became manifest though they hated it.)

﴿وَمِنْهُمْ مَّن يَقُولُ ائْذَن لِّي وَلاَ تَفْتِنِّى أَلا فِى الْفِتْنَةِ سَقَطُواْ وَإِنَّ جَهَنَّمَ لَمُحِيطَةٌ بِالْكَـفِرِينَ ﴾

(49. And among them is he who says: "Grant me leave and put me not into trial.'' Surely, they have fallen into trial. And verily, Hell is surrounding the disbelievers.) Allah says, some hypocrites say to you, O Muhammad ,

﴿ائْذَن لِّي﴾

(Grant me leave), to stay behind,

﴿وَلاَ تَفْتِنِّى﴾

(and put me not into trial.), if I go with you and see the women of the Romans. Allah, the Exalted, replied,

﴿أَلا فِى الْفِتْنَةِ سَقَطُواْ﴾

5(Surely, they have fallen into trial) because of the statement they uttered. Muhammad bin Ishaq reported from Az-Zuhri, Yazid bin Ruwman, `Abdullah bin Abi Bakr, `Asim bin Qatadah and several others that they said, "The Messenger of Allah said to Al-Jadd bin Qays from Bani Salimah,

«هَلْ لَكَ يَا جَدُّ الْعَامَ فِي جَلَادِ بَنِي الْأَصْفَرِ؟»

(`Would you like to fight the yellow ones (Romans) this year) He said, `O Allah's Messenger! Give me permission (to remain behind) and do not cause Fitnah for me. By Allah! My people know that there is not a man who is more fond of women than I. I fear that if I see the women of the yellow ones, I would not be patient.' The Messenger of Allah turned away from him and said,

«قَدْ أَذِنْتُ لَك»

(I give you permission.) In Al-Jadd's case, this Ayah was revealed,

﴿وَمِنْهُمْ مَّن يَقُولُ ائْذَن لِّي وَلاَ تَفْتِنِّى﴾

(And among them is he who says: "Grant me leave and put me not into trial.'') Therefore, Allah says that the Fitnah that he fell into because of not joining the Messenger of Allah (in Jihad) and preferring his safety to the safety of the Messenger is worse than the Fitnah that he falsely claimed to fear.'' It was reported from Ibn `Abbas, Mujahid and several others that this Ayah was revealed in the case of Al-Jadd bin Qays, who was among the chiefs of Bani Salimah. It is also recorded in the Sahih that the Messenger of Allah asked,

«مَنْ سَيِّدُكُمْ يَا بَنِي سَلَمَةَ؟»

(Who is your chief, O Bani Salamah) They said, "Al-Jadd bin Qays, although we consider him a miser.'' The Messenger of Allah said,

«وَأَيُّ دَاءٍ أَدْوَأُ مِنَ الْبُخْلِ وَلَكِنْ سَيِّدُكُمْ الْفَتَى الْجَعْدُ الْأَبْيَضُ بِشْرُ بْنُ الْبَرَاءِ بْنِ مَعْرُور»

(There is not a disease worse than stinginess! Therefore, your chief is the white young man with curly hair, Bishr bin Al-Bara' bin Ma'rur.) Allah said next,

﴿وَإِنَّ جَهَنَّمَ لَمُحِيطَةٌ بِالْكَـفِرِينَ﴾

(And verily, Hell is surrounding the disbelievers.) and they will never be able to avoid, avert, or escape from it.

﴿إِن تُصِبْكَ حَسَنَةٌ تَسُؤْهُمْ وَإِن تُصِبْكَ مُصِيبَةٌ يَقُولُواْ قَدْ أَخَذْنَا أَمْرَنَا مِن قَبْلُ وَيَتَوَلَّواْ وَّهُمْ فَرِحُونَ - قُل لَّن يُصِيبَنَآ إِلاَّ مَا كَتَبَ اللَّهُ لَنَا هُوَ مَوْلَـنَا وَعَلَى اللَّهِ فَلْيَتَوَكَّلِ الْمُؤْمِنُونَ ﴾

(50. If good befalls you, it grieves them, but if a calamity overtakes you, they say: "We took our precaution beforehand,'' and they turn away rejoicing.) (51. Say: "Nothing shall ever happen to us except what Allah has ordained for us. He is our Mawla (protector).'' And in Allah let the believers put their trust.)