Qur'an 3:13

قَدْ كَانَ لَكُمْ ءَايَةٌ فِى فِئَتَيْنِ ٱلْتَقَتَا ۖ فِئَةٌ تُقَـٰتِلُ فِى سَبِيلِ ٱللَّهِ وَأُخْرَىٰ كَافِرَةٌ يَرَوْنَهُم مِّثْلَيْهِمْ رَأْىَ ٱلْعَيْنِ ۚ وَٱللَّهُ يُؤَيِّدُ بِنَصْرِهِۦ مَن يَشَآءُ ۗ إِنَّ فِى ذَٰلِكَ لَعِبْرَةً لِّأُو۟لِى ٱلْأَبْصَـٰرِ

There was a token for you in two hosts which met: one army fighting in the way of Allah, and another disbelieving, whom they saw as twice their number, clearly, with their very eyes. Thus Allah strengtheneth with His succour whom He will. Lo! herein verily is a lesson for those who have eyes.