Allah, the Exalted, says:
"The believers are nothing else than brothers (in Islamic religion)".
"(Nuh said) I give sincere advice to you".
"(And Hud said) And I am a trustworthy adviser (or well-wisher) for you". (7:68)
Tamim bin Aus Ad-Dari (May Allah be pleased with him) reported: The Prophet (PBUH) said, "Ad-Deen is sincerity". We said: "For whom?'' He replied, "For Allah, His Book, His Messenger and for the leaders of the Muslims and their masses".
This Hadith stresses the importance and merits of general sincerity. Sincerity for Allah here means that one must have true faith in Him and He should be worshipped with full devotion and sincerity. Sincerity for the Qur'an means that one should confirm its truth with one's full heart and mind, recite it regularly, act upon the injunctions contained in it with meticulous care and strictly avoid its misinterpretation. Sincerity of the Prophet (PBUH) means sincere confirmation of his Prophethood, faithful obedience of his orders and adherence to his Sunnah. The goodwill of the Muslim rulers stands here for co-operating with them in their lawful orders and obedience of their such orders which are free from any trace of sin. If they deviate from the Straight Path they should be persuaded to turn to virtue. One should not revolt against them unless they commit infidelity. The goodwill of the Muslim masses means that one should work for the betterment of their life in this world and the Hereafter. They should be provided the right guidance, induced to perform good deeds and deterred from evils.
Jarir bin `Abdullah (May Allah be pleased with him) reported: I made my covenant with Messenger of Allah (PBUH) on the observance of Salat, payment of Zakat, and giving counsel to Muslim.''
[Al-Bukhari and Muslim].
This Hadith emphasizes the importance of goodwill to all the Muslims to the extent that the Prophet (PBUH) would require his Companions to vow for their goodwill giving counsel to each other in the same way as he did in the case of most important obligations like Salat and Zakat.
Anas (May Allah be pleased with him) reported: The Prophet (PBUH) said, "No one of you becomes a true believer until he likes for his brother what he likes for himself".
[Al-Bukhari and Muslim].
We learn from this Hadith about the importance and virtue of mutual love among the Muslims. If we act upon the injunctions mentioned in this Hadith, the Muslim societies will be immediately purged of the evils like exploitation, bribery, dishonesty, falsehood, cheating, forgery, etc., which are rampant in them at present. Islam has taught golden principles to its followers who have unfortunately neglected them and in consequence are leading a life of utter disgrace and moral turpitude. May Allah guide them to the Straight Path.