Sahih al-Bukhari 4516Book 65, Hadith 41
حَدَّثَنَا إِسْحَاقُ، أَخْبَرَنَا النَّضْرُ، حَدَّثَنَا شُعْبَةُ، عَنْ سُلَيْمَانَ، قَالَ سَمِعْتُ أَبَا وَائِلٍ، عَنْ حُذَيْفَةَ، {وَأَنْفِقُوا فِي سَبِيلِ اللَّهِ وَلاَ تُلْقُوا بِأَيْدِيكُمْ إِلَى التَّهْلُكَةِ} قَالَ نَزَلَتْ فِي النَّفَقَةِ.
Hudhaifa said, "The Verse:-- "And spend (of your wealth) in the Cause of Allah and do not throw yourselves in destruction," (2.195) was revealed concerning spending in Allah's Cause (i.e. Jihad).