Qur'an 8:42

إِذْ أَنتُم بِٱلْعُدْوَةِ ٱلدُّنْيَا وَهُم بِٱلْعُدْوَةِ ٱلْقُصْوَىٰ وَٱلرَّكْبُ أَسْفَلَ مِنكُمْ ۚ وَلَوْ تَوَاعَدتُّمْ لَٱخْتَلَفْتُمْ فِى ٱلْمِيعَـٰدِ ۙ وَلَـٰكِن لِّيَقْضِىَ ٱللَّهُ أَمْرًا كَانَ مَفْعُولًا لِّيَهْلِكَ مَنْ هَلَكَ عَنۢ بَيِّنَةٍ وَيَحْيَىٰ مَنْ حَىَّ عَنۢ بَيِّنَةٍ ۗ وَإِنَّ ٱللَّهَ لَسَمِيعٌ عَلِيمٌ

When ye were on the near bank (of the valley) and they were on the yonder bank, and the caravan was below you (on the coast plain). And had ye trysted to meet one another ye surely would have failed to keep the tryst, but (it happened, as it did, without the forethought of either of you) that Allah might conclude a thing that must be done; that he who perished (on that day) might perish by a clear proof (of His Sovereignty) and he who survived might survive by a clear proof (of His Sovereignty). Lo! Allah in truth is Hearer, Knower.