مِشْكَاةُ الْمَصَابِيحِ
Mishkat al-Masabih 3862
Jihad
Preparing Equipment for Jihad - Section 1
وَعَنْهُ قَالَ: سَمِعْتُ رَسُولَ اللَّهِ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ يَقُولُ: «سَتُفْتَحُ عَلَيْكُمُ الرُّومُ وَيَكْفِيكُمُ اللَّهُ فَلَا يَعْجِزْ أَحَدُكُمْ أَنْ يَلْهُوَ بِأَسْهُمِهِ» . رَوَاهُ مُسلم
He told that he heard God's Messenger say, “The Byzantines will be defeated at your hands and God will defend you, but let none of you be so careless as not to employ his arrows.”* * i.e. they must not neglect to practise archery. The idea is that although God defends them, this does not absolve them from effort. Muslim transmitted it.
Mishkat al-Masabih, 3862صَحِيح (الألباني)