Surah 18. Al-Kahf, Ayah 104

Many people have such a smug sense of self-righteousness that while they go on doing wrong, they think that they are acquiring merit. So, in charity, all the elements that make for outward show or selfishness (as to get some worldly advantage) nullify the deed of charity. In the same way hypocrites sometimes affect to be surprised that their declared effort for somebody's good is not appreciated, when they are really seeking some hidden gain or false glory for themselves. The sincere are only those who believe in their spiritual responsibility and act as in Allah's sight.