Surah Al-Anfal (The Spoils of War), Verse 66

اَلْـٰٔنَ خَفَّفَ اللّٰهُ عَنْكُمْ وَعَلِمَ اَنَّ فِیْكُمْ ضَعْفًا فَاِنْ یَّكُنْ مِّنْكُمْ مِّائَةٌ صَابِرَةٌ یَّغْلِبُوْا مِائَتَیْنِ وَاِنْ یَّكُنْ مِّنْكُمْ اَلْفٌ یَّغْلِبُوْۤا اَلْفَیْنِ بِاِذْنِ اللّٰهِ وَاللّٰهُ مَعَ الصّٰبِرِیْنَ ۟

Al'aana khaffafal laahu 'ankum wa 'alima anna feekum da'faa; fa-iny yakum minkum mi'atun saabiratuny yaghliboo mi'atayn; wa iny-yakum minkum alfuny yaghlibooo alfaini bi iznil laah; wallaahu ma'as saabireen

“For the present, Allah hath lightened your (task), for He knoweth that there is a weak spot in you: But (even so), if there are a hundred of you, patient and persevering, they will vanquish two hundred, and if a thousand, they will vanquish two thousand, with the leave of Allah: for Allah is with those who patiently persevere.”

Quran 8:66 (Yusuf Ali Translation)