Riyad as-Salihin 110

Abu Mas'ud 'Uqbah bin 'Amr Al-Ansari (May Allah be pleased with him) said: When the Ayah enjoining Sadaqah (charity) was revealed,* we used to carry loads on our backs to earn something that we could give away in charity. One person presented a considerable amount for charity and the hypocrites said: "He has done it to show off." Another one gave away a few Sa' of dates and they said: "Allah does not stand in need of this person's dates". Thereupon, it was revealed: "Those who defame such of the believers who give charity (in Allah's Cause) voluntarily, and such who could not find to give charity (in Allah's Cause) except what is available to them..." (9:79) [Al- Bukhari and Muslim]. * This is the version of Al-Bukhari.