Surah At-Taubah, Ayat 78-79

Ayat 78. Know they not that Allah knows their secret ideas, and their Najwa (secret counsels), and that Allah is the All-Knower of the unseen.

Ayat 79. Those who defame such of the believers who give charity (in Allah's Cause) voluntarily, and those who could not find to give charity (in Allah's Cause) except what is available to them, so they mock at them (believers), Allah will throw back their mockery on them, and they shall have a painful torment. 

Hazrat Uqbah bin Al-Harith (May Allah be pleased with him) said: Once I performed the 'Asr prayer in Al-Madinah behind the Prophet [SAWW](PBUH). He [SAWW](PBUH) got up quickly after finishing the prayer with Taslim, and stepping over the people, went to one of the rooms of his wives. The people were startled at his haste, and when he came out and saw their astonishment at his urgency he said, "I recalled that there was left with me some gold which was meant for charity; I did not like to keep it any longer, so I gave orders that it should be distributed". [Al-Bukhari Hadith # 851].   

Lesson : as mentioned above in Surah At-Taubah Ayat 79 "and those who could not find to give charity (in Allah's Cause) except what is available to them, so they mock at them (believers)", 1. A person should not keep such a thing because of which his attention is diverted from Allah (SWT) towards that thing. 2. Although it is undesirable to jump over the neck of people in ordinary circumstances but it is permissible when special conditions warrant it.