Muslims must never do good and expect worldly gains in return:
A true Muslim must always do good and never expect any worldly gains in return. Allah Almighty said:
"Those who spend their wealth for increase in self-purification, And have in their minds No favour from anyone For which a reward Is expected in return, But only the desire To seek for the Countenance Of their Lord Most High; And soon will they Attain (complete) satisfaction. (The Noble Quran, 92:18-21)"
"O my people! I ask of you no reward for this (Message). My reward is from none but Him who created me: Will ye not then understand? (The Noble Quran, 11:51)"
"Obey those who ask no reward of you (for themselves), and who have themselves received Guidance. (The Noble Quran, 36:21)"
"Those who spend their substance in the cause of God, and follow not up their gifts with reminders of their generosity or with injury,-for them their reward is with their Lord: on them shall be no fear, nor shall they grieve. (The Noble Quran, 2:262)"
"O ye who believe! cancel not your charity by reminders of your generosity or by injury,- like those who spend their substance to be seen of men, but believe neither in God nor in the Last Day. They are in parable like a hard, barren rock, on which is a little soil: on it falls heavy rain, which leaves it (Just) a bare stone. They will be able to do nothing with aught they have earned. And God guideth not those who reject faith. And the likeness of those who spend their substance, seeking to please God and to strengthen their souls, is as a garden, high and fertile: heavy rain falls on it but makes it yield a double increase of harvest, and if it receives not Heavy rain, light moisture sufficeth it. God seeth well whatever ye do. (The Noble Quran, 2:264-265)"
"And whatever ye spend in charity or devotion, be sure God knows it all. But the wrong-doers have no helpers. (The Noble Quran, 2:270)"
"Those who spend (freely), whether in prosperity, or in adversity; who restrain anger, and pardon (all) men;- for God loves those who do good;- (The Noble Quran, 3:134)"
"Not those who spend of their substance, to be seen of men, but have no faith in God and the Last Day: If any take the Evil One for their intimate, what a dreadful intimate he is! (The Noble Quran, 4:38)"
"The parable of those who spend their substance in the way of God is that of a grain of corn: it groweth seven ears, and each ear Hath a hundred grains. God giveth manifold increase to whom He pleaseth: And God careth for all and He knoweth all things. (The Noble Quran, 2:261)"
A Muslim must never go after worldly gains. It is important to always do good for the sake of Allah Almighty and not for the sake of popularity or self recognition. A good work is fruitless if it's not done for the right reasons. Therefore my dear Muslim brother or sister, you should always do good things for the sake of Allah Almighty alone so He would further purify your soul, and bless you with both worldly rewards and Hereafter rewards.