O ye who believe ! fear Allah as HE should be feared;
and let not death overtake you except when you are in a state of submission.
And hold fast, all together, to the rope of Allah and be not divided; and remember the favour of Allah which HE bestowed upon you when you were enemies and HE united your hearts in love, so that by HIS grace you became as brothers; and you were on the brink of a pit of fire and HE saved you from it. Thus does Allah explain to you HIS commandments that you may be guided.
And let there always be among you a body of men who should invite to goodness, and enjoin virtue and forbid evil. And it is they who shall prosper. (3:103-105)

Abdullah ibn Mas'ud (r.a) relates that the Holy Prophet (sa) said: Truth guides to virtue and virtue guides to Paradise. A person persists in telling the truth till in the sight of Allah he is named Truthful. Lying leads to vice and vice leads to the Fire; and a person goes on lying till in the sight of Allah he is named a liar (Bokhari and Muslim).