Allah said,
وَلَوْ أَرَادُواْ الْخُرُوجَ
(And if they had intended to march out,), with you to participate in Jihad
لأَعَدُّواْ لَهُ عُدَّةً
(certainly, they would have made some preparation for it) they would have prepared for such task,
وَلَـكِن كَرِهَ اللَّهُ انبِعَاثَهُمْ
(but Allah was averse to their being sent forth) Allah hated that they should go with you,
فَثَبَّطَهُمْ
(so He made them lag behind, and stay away from Jihad,
وَقِيلَ اقْعُدُواْ مَعَ الْقَـعِدِينَ
(and it was said (to them): "Sit you among those who sit (at home)") as a part of what was decreed for them not that He legislated that they stay behind. Allah then explained why He disliked that they march with the believers, saying,
لَوْ خَرَجُواْ فِيكُم مَّا زَادُوكُمْ إِلاَّ خَبَالاً
(Had they marched out with you, they would have added to you nothing except disorder), because they are cowards and failures,
ولاّوْضَعُواْ خِلَـلَكُمْ يَبْغُونَكُمُ الْفِتْنَةَ
(and they would have hurried about in your midst sowing sedition among you) They would have rushed to spread false stories, hatred and discord among you,
وَفِيكُمْ سَمَّـعُونَ لَهُمْ
(and there are some among you who would have listened to them.) who would have obeyed them, given preference to their speech and words and asked them for advice, unaware of the true reality of these hypocrites. This might have caused corruption and great evil between the believers. Muhammad bin Ishaq said, "Those who sought permission (from the Messenger to lag behind) included some of the chiefs, such as `Abdullah bin Ubayy bin Salul and Al-Jadd bin Qays, who were masters of their people. Allah also made them lag behind because He knew that if they went along with the Messenger ﷺ they would sow sedition in his army." There were some in the Prophet's army who liked these chiefs and were ready to obey them, because they considered them honorable,
وَفِيكُمْ سَمَّـعُونَ لَهُمْ
(and there are some among you who would have listened to them) 9:47. Allah next reminds of His perfect knowledge, saying,
وَاللَّهُ عَلِيمٌ بِالظَّـلِمينَ
(And Allah is the All-Knower of the wrongdoers.) Allah says that He knows what occurred, what will occur and if anything would have occurred, how it would occur, such as,
لَوْ خَرَجُواْ فِيكُم مَّا زَادُوكُمْ إِلاَّ خَبَالاً
(Had they marched out with you, they would have added to you nothing except disorder,) indicating what they would have done had they marched, even though they did not. Allah said in similar Ayat,
وَلَوْ رُدُّواْ لَعَـدُواْ لِمَا نُهُواْ عَنْهُ وَإِنَّهُمْ لَكَـذِبُونَ
(But if they were returned (to the world), they would certainly revert to that which they were forbidden. And indeed they are liars.) 6:28,
وَلَوْ عَلِمَ اللَّهُ فِيهِمْ خَيْرًا لأَسْمَعَهُمْ وَلَوْ أَسْمَعَهُمْ لَتَوَلَّواْ وَّهُم مُّعْرِضُونَ
(Had Allah known of any good in them, He would indeed have made them listen; and even if He had made them listen, they would but have turned away with aversion (to the truth)) 8:23, and,
وَلَوْ أَنَّا كَتَبْنَا عَلَيْهِمْ أَنِ اقْتُلُواْ أَنفُسَكُمْ أَوِ اخْرُجُواْ مِن دِيَـرِكُمْ مَّا فَعَلُوهُ إِلاَّ قَلِيلٌ مِّنْهُمْ وَلَوْ أَنَّهُمْ فَعَلُواْ مَا يُوعَظُونَ بِهِ لَكَانَ خَيْراً لَّهُمْ وَأَشَدَّ تَثْبِيتاً - وَإِذاً لاّتَيْنَـهُمْ مِّن لَّدُنَّـآ أَجْراً عَظِيماً - وَلَهَدَيْنَـهُمْ صِرَطاً مُّسْتَقِيماً
(And if We had ordered them (saying), "Kill yourselves (the innocent ones kill the guilty ones) or leave your homes," very few of them would have done it; but if they had done what they were told, it would have been better for them, and would have strengthened their conviction. And indeed We would then have bestowed upon them a great reward from Ourselves. And indeed We would have guided them to the straight way) 4:66-68.