Tirmidhi

In the Noble Qur’an, giving charity (sadaqah) secretly is considered superior. Although giving charity openly is also regarded as good, because each has its own distinct benefits. Since there is a strong risk of showing off (riya) in giving charity openly, it is therefore not superior. However, at times, giving charity openly can also be superior, when the intention is to encourage and motivate others. Some scholars have reconciled the matter in this way: obligatory charity (fard sadaqah) should be given openly, because this will protect one from suspicion and accusation. Others will also be encouraged. The possibility of showing off is also less, because an obligatory act must be performed in any case. However, voluntary charity (nafl sadaqah) should be given secretly, because this is a matter between Allah and the servant. It should remain concealed, whereas an obligatory act cannot remain hidden, just as it is obligatory to perform the obligatory prayer (fard salah) in front of everyone (in congregation), while it is superior to perform voluntary prayer (nafl salah) at home, so that there is no suspicion of showing off.

1333. Commentary: Benefit: That is, a person receives reward according to his intention. If raising the voice in recitation is intended to encourage others, then certainly it is permissible, desirable, and rewardable; otherwise, it is not.