Sahih al-Bukhari, Volume 4, Book 55, Hadith 592 (USC-MSA) ⓘ

Narrated Salama bin Al-Akwa`: The Prophet passed by some persons of the tribe of Aslam practicing archery (i.e. the throwing of arrows) Allah's Messenger said, "O offspring of Ishmael! Practice archery (i.e. arrow throwing) as your father was a great archer (i.e. arrow-thrower). I am with (on the side of) the son of so-and-so-." Hearing that, one of the two teams stopped throwing. Allah's Messenger asked them, ' Why are you not throwing?" They replied, "O Allah's Messenger! How shall we throw when you are with the opposite team?" He said, "Throw, for I am with you all."

حَدَّثَنَا قُتَيْبَةُ بْنُ سَعِيدٍ، حَدَّثَنَا حَاتِمٌ، عَنْ يَزِيدَ بْنِ أَبِي عُبَيْدٍ، عَنْ سَلَمَةَ بْنِ الأَكْوَعِ ـ رضى الله عنه ـ قَالَ مَرَّ النَّبِيُّ صلى الله عليه وسلم عَلَى نَفَرٍ مِنْ أَسْلَمَ يَنْتَضِلُونَ، فَقَالَ رَسُولُ اللَّهِ صلى الله عليه وسلم ‏"‏ ارْمُوا بَنِي إِسْمَاعِيلَ، فَإِنَّ أَبَاكُمْ كَانَ رَامِيًا، وَأَنَا مَعَ بَنِي فُلاَنٍ ‏"‏‏.‏ قَالَ فَأَمْسَكَ أَحَدُ الْفَرِيقَيْنِ بِأَيْدِيهِمْ، فَقَالَ رَسُولُ اللَّهِ صلى الله عليه وسلم ‏"‏ مَا لَكُمْ لاَ تَرْمُونَ ‏"‏‏.‏ فَقَالُوا يَا رَسُولَ اللَّهِ، نَرْمِي وَأَنْتَ مَعَهُمْ قَالَ ‏"‏ ارْمُوا وَأَنَا مَعَكُمْ كُلِّكُمْ ‏"‏‏.‏