"But some of the desert Arabs believe in God and the Last Day, and look on their payments as pious gifts bringing them nearer to God and obtaining the prayers of the Apostle. Aye, indeed they bring them nearer (to Him): soon will God admit them to His Mercy: for God is Oft-forgiving, Most Merciful."
 

(Holy Qur'an (Yusufali) 9:99)

"Whoso desires power (should know that) all power belongs to Allah. Unto Him good words ascend, and the pious deed doth He exalt; but those who plot iniquities* theirs will be an awful doom; and the plotting of such (folk) will come to naught."
 
*iniquities means gross immorality or injustice; wickedness
 

(Holy Qur'an (Yusufali) 35:10)

"I advise you, O people, to be pious, as piety is the best provision for the next world and the best protection against sin. It is a provision which will help you to the Heaven and it is a shelter which will protect you from the Wrath of God. It is an advice which is the best law giver of God, the Holy Prophet (s.a.s.) has given you and it is accepted and remembered by the best mankind. He was an advisor who has explained everything and those who accepted and followed him succeeded in attaining the Blessings of God.
 
O people! piety prevents good people from indulging in sins and vices, it makes them God fearing, it persuades them to spend their nights in His worship and to pass their days in doing duties towards man and God; and the exertion of prayers and labour of doing their duty gives them pleasure and satisfaction. They always keep their death before their mind's eye, they enhance the quality and quantity of their performances, and keeping their eyes on the next world they regard with indifference the pleasures and profits of this world."
 

(Nahjul Balagha: Sermons, letters and saying of Hazrat Ali (Second American edition, 1981), Khutba 117, p. 87)