ٱلْـَٰٔنَ خَفَّفَ ٱللَّهُ عَنكُمْ وَعَلِمَ أَنَّ فِيكُمْ ضَعْفًا ۚ فَإِن يَكُن مِّنكُم مِّا۟ئَةٌ صَابِرَةٌ يَغْلِبُوا۟ مِا۟ئَتَيْنِ ۚ وَإِن يَكُن مِّنكُمْ أَلْفٌ يَغْلِبُوٓا۟ أَلْفَيْنِ بِإِذْنِ ٱللَّهِ ۗ وَٱللَّهُ مَعَ ٱلصَّٰبِرِينَ
Commentary:
This verse does not abrogate the previous verse, but only temporarily relieves Muslims in view of the then existing condition of their faith. Their faith, though sincere and true, was "weak" as compared with its future condition when it was to grow stronger by their witnessing more and more heavenly signs and by their becoming more and more organized.
The words, For the present Allah has lightened your burden, show that the previous verse contains not a prophecy, but a commandment. It does not announce by way of prophecy that Muslims will prevail over an enemy ten times their number; it simply gives the injunction that if twenty believers have to face 200 disbelievers, they must fight them, and that if they turn their backs, they will be sinners. In the present verse, however, in view of the then weak condition of Muslims, the limit of disparity has been reduced to twice the number of the believers.
History tells us that in later times, Muslims had sometimes to fight an enemy even more than ten times their number and still they were victorious. Thus, at the Battle of Yarmuk the Muslim army numbered 30,000, according to the lowest calculation, while the enemy numbered at least 600,000 (the highest figures being respectively 60,000 and 1,000,000) and the battle ended in a decisive victory for the Muslims.
The verse should not be understood to abrogate the preceding one. The two verses refer to two different states of the Muslim Community. In the beginning they were weak, ill-equipped and ill-trained in the art of war. In that state of weakness they could successfully fight against only their double number. But as with the passage of time their all-round condition, fighting experience and military resources had very much improved they could defeat an enemy ten times their number. In the battles of Badr, Uhud and of the Trench, the disparity between the number of forces of both sides progressively increased, yet the Muslims quite successfully held their own, till at the Battle of Yarmuk, mere 60,000 Muslims defeated an army of more than a million strong.