O you who have believed, fear Allah and be with those who are true. (At-Tawbah 9:119)
Moreover, the Prophet Muhammad (peace be upon him) has nicely explained that only when faith is firm and strong, strong and lasting morals would be developed, but if the moral character is low in faith, it will be weak accordingly.
Who is immodest and ill-mannered or who adopts bad habits, loses his faith:
The Prophet (peace be upon him) said, “Modesty and faith are twins. One who gives up one has to lose the other too.” (Al-Hakim)
Once the Prophet Muhammad (peace be upon him) passed by a person of Al-Ansar who was scolding his brother on his excessive shyness. The Prophet (peace be upon him) told the man to leave him because shyness is a part of faith.
A man who harasses his neighbour and makes him suffer any kind of damage is called cruel and stonehearted by Islam. In this context, the Prophet (peace be upon him) says:
“By Allah, he cannot be a true believer; By Allah, he cannot be a true believer; By Allah, he cannot be a true believer. He was asked: ‘Who?’ He answered: “(The one) whose neighbour is not safe from his wrongdoings.” (Al-Bukhari)
Moreover, the Prophet Muhammad (peace be upon him) linked the good deeds to faith itself, and said:
“Anybody who believes in Allah and the Last Day should not harm his neighbour, and anybody who believes in Allah and the Last Day should entertain his guest generously and anybody who believes in Allah and the Last Day should talk what is good or keep silent.” (Al-Bukhari)
Through the firm and perfect faith, noble qualities are nurtured, developed and safeguarded until the good manners bear their fruits. That is why Islam regards good manner as an inseparable part of faith.
Who lags behind in acting according to the moral values of Islamic framework he undermines his faith. Such people were warned against by the Prophet (peace be upon him), and the community has been asked to be careful of them.
Who performs various forms of worship without understanding their significance can only be a man who had not understood the spirit of the worship or has been unable to rise to the real standard of faith.
If a person has high moral character, his worship results in good rewards and nearness to the Almighty Allah. But the one who is deprived of good manners, his worship is useless.
It was narrated by Imam Ahmad that a person asked the Prophet: “O Messenger of Allah! There is a woman who is very famous for her prayers, fasting and a lot of charities, but she talks rudely with her neighbours, what will be her fate?” He replied that she would go to Hell. Then that person asked: “O Messenger of Allah! Another woman does not do much prayer and fasting; she gives only pieces of cheese in charity but she does not harm her neighbours.” He replied: “She will be in the Paradise.”
Islam is distinct from Hinduism in the value of equality between all people, while Hinduism is based on the distinction between human beings. This difference between them is like the difference between the darkness and light.