Muslim)that the Prophet (peace be upon him) said to 'Aly (may Allah be pleased with him), when he sent him to the Jews of Khaybar to call them to Islam and explain to them Allah's Right on them, "By Allah! If Allah guides one man through you it is better for you than red camels (i.e. the most valuable possession."
It is obligatory on Muslims in all places and at all times to advise one another, cooperate in righteousness and piety, advise one another to adhere to AlHaqq and be patient over it, and perform the duty of Da'wah to Islam with nonMuslims.
By Al'Asr (the time). Verily, man is in loss, Except those who believe (in Islâmic Monotheism) and do righteous good deeds, and recommend one another to the truth [i.e. order one another to perform all kinds of good deeds (AlMa'ruf) which Allâh has ordained, and abstain from all kinds of sins and evil deeds (AlMunkar which Allâh has forbidden], and recommend one another to patience (for the sufferings, harms, and injuries which one may encounter in Allâh's Cause during preaching His religion of Islâmic Monotheism or Jihâd).
Help you one another in AlBirr and AtTaqwâ (virtue, righteousness and piety); but do not help one another in sin and transgression.
"The Din is sincerity, the Din is sincerity, the Din is sincerity." They said, "To whom, O Messenger of Allah?" He answered, "To Allah, His Book, His Messenger, and the Imams (leaders) of Muslims and their common people." (Agreed upon by AlBukhari and Muslim)