The Characteristics of a Muslim
The Holy Prophet [s] said: "Shall I not introduce 'a believer' to you? A believer is the one whom other believers trust with their souls and wealth. Shall I not introduce 'a Muslim' to you? A Muslim is the one from whose hand and tongue other Muslims are safe.... It is unlawful (Haram) for a believer to do wrong against another believer, or leave him/her in a lurch, or backbite against him/her, or suddenly reject him/her."
AI-Kafi, vol. 2, p. 235
Imam Sadiq [a] said: "A Muslim believer must not attend a meeting wherein Allah laws are being disobeyed and the one is not in a position to stop it."
Usul-i-Kafi, vol. 2, p. 374
Imam Sadiq [a] said: "He who habitually tells the truth, his deeds are purified; Allah increases the sustenance of the one whose intention is good; and he who treats his family members well, Allah prolongs the length of his life."
Khisal by Saduq, vol. 1 p. 88
Imam Amir ul Mu'mineen Ali [a] said: "A man came to the Prophet [s] and asked him to teach him an action so that both Allah, the Exalted, and people would love him, his wealth would increase, his body would be healthy, his life time would last long, and he would be raised with him (the Prophet). Then, he [s] said: 'These are six traits which need six qualities:
1. If you want Allah to love you, be afraid of Him and guard yourself against sin.
2. If you want people to love you, be benevolent to them and decline what they have in their hands.
3. If you want Allah to increase your wealth, then give its alms tax.
4. If you want Allah to make your body healthy, pay charity more frequently.
5. If you want Allah to prolong your lifetime, then have regard for your kinship.
6. And, if you want Allah to raise you with me, then do prolong your prostrations before Allah, the One, the Dominator.'"
Safinat-uI-Bihar, vol. 1, p. 599
Imam Rida, the eighth Imam, [a] said: A Muslim believer is not a true believer unless there are three virtues in him: the manner of his lord, the manner of his Prophet, and the manner of his Imam. Then, the manner of his Lord is: concealing his secrets; hence Allah, to Whom belong Might and Majesty, said: 'The Knower of the Unseen! So He does not reveal His secrets to any, except to him whom He chooses as an apostle,...' 
Then, the manner of his Prophet is compliance with people, when surely, Allah, Almighty and Glorious, commissioned His prophet to favour people and He has said: 'Practice forgiveness and enjoin good and turn away from the ignorant.'
Then the manner of his Imam is (to be firm and) being patient on good days and bad days, when, verily, Allah to whom belong Might and Majesty, says: 'And (they) are patient in distress and affliction'." 
'Uyun-ul-Akhbar-ur-Rida, vol.1, p.256
Imam Muhammad ibn Ali, the nineth Imam [a] said:
"A Muslim believer should obtain these three virtues:
Success granted by Allah, be an admonisher of his self, and find approval from the one who advises him."
Ali ibn Husayn [a] the fourth Imam, was once asked how he, the son of the Messenger of Allah began each morning, and he [a] replied: "I begin each morning while I am demanded of eight virtues:
Allah, the Exalted, demands of me the obligatory; the Prophet [s] demands of me his tradition (Sunnah); family dependents demand of me food (material); the self looks for desires; Satan demands me (to commit) sin; the two protective angels demand of me virtuousness, the angel of death demands of me the spirit and, the grave demands of me my body.
Therefore, I am, surrounded by these traits, demanded."
Bihar-ul-Anwar, vol. 76, p. 15
Imam Sadiq [a] said: "Verily everything is intimidated by a believer because the religion of Allah causes him to be powerful, and he is not intimidated by anything, which (epithet) is the characteristic of any believer."
Bihar-ul-Anwar, vol. 67, p. 305
 Sura Al-Jinn, No.72, verses 26 & 27
 Sura Al-Baqarah, No.2, verse 177