Abu Usaid reported the Apostle of Allaah ﷺ as saying to us at the battle of Badr when he drew up in rows. When they came near you, shoot arrows at them, but do not use all your arrows.  

قَالَ رَسُولُ اللَّهِ ﷺ حِينَ اصْطَفَفْنَا يَوْمَ بَدْرٍ إِذَا أَكْثَبُوكُمْ يَعْنِي إِذَا غَشُوكُمْ فَارْمُوهُمْ بِالنَّبْلِ وَاسْتَبْقُوا نَبْلَكُمْ