O you who believe! Do not nullify your charities by reproaches and causing offence
(Sūratul Baqarah, No.2, Āyat 264)
Giving charity is a noble act. It is, or should be, a selfless act when a human being goes beyond the selfish desires of the soul and gives to others. Certain etiquettes enhance the charity that is given while other behaviors undermine its beauty.
One behavior that robs charity of its purity is outlined in the verse above. Believers are told not to follow charity with mann and azā. Mann is described as reminding the other person of the favors that were done and making them feel obliged. Azā is to hurt the other person, physically or emotionally. It could be by telling others about it and robbing him of self-respect, using harsh words with him, having unrealistic expectations of reciprocity and other similar behaviors.
The verse continues with an example of how such charity is worthless and unproductive. Allah says: Their parable is that of a rock covered with soil, a downpour strikes it, leaving it bare. The soil is there and it has water. But because it is on hard stone it cannot grow. It needs deep soft soil to grow and be productive. Without the appropriate foundation, nothing can grow. According to Tafsīr Majma‘ al-Bayān, just as the rain took away the soil from the stone and it cannot come back, reminding others of charity takes away its purity and beauty. Once it is done the value of the charity cannot be retrieved.
Reminding others of favors done to them shows lack of sincerity. According to the verse the action is like that of the one who performs deeds to show off to others. Allāmah Tabātabā’ī points out that Allah does not say the person who does the reminding is showing off to others. Rather Allah says he is like the one who shows off. This is because Allah is talking to believers, who started off with the correct intention but lost it after performing the deed.
The Holy Prophet (s) says: Whoever does good to his brother in faith and then reminds them about it making them feel obliged, Allah annuls the reward of that action while a burden [of sin] remains and his efforts are not appreciated (Wasā’il al-Shī‘ah, 9: 452). Imam Zaynul ‘Ābidīn (a) says in Sahīfa Sajjādiyya: O Allah . . . let good flow out from my hands upon the people and efface it not by my making them feel obliged (Du‘ā. No. 20).
Reminding others of favors done to them is rooted in pride and self-conceit. Humility demands that we think nothing of what we do for others. Two of the qualities that Imam Ali Ridhā (a) describes as maturity of intellect are when a person sees the little good others do for him as great and his own great good as little (Bihārul Anwār, 78: 336).
Recite this verse when you do a good deed for others. Refrain from remembering it and keeping it in mind as something the other person owes you. It is you who owe the person. The Tawfīq and chance to do it is itself is a favor over you, firstly from God and then from the person you favored. Such is the noble attitude of a believer.
Āyatullāh Nāsir Makārim Shirāzī (ed.), Tafsīr-e Namūne;
Allāmah Muhammad Husayn Tabātabā’ī, Tafsīr al-Mīzān;
Shaykh Tabarsī, Majma‘ al-Bayān fī Tafsīr al Quran; http://www.islamquest.net/fa/