Shaykh Bin Baz said, “The ruling (upon the one who who fails to enjoin what is good and forbid what is evil when he is able to do that) is that he is disobeying Allaah and His Messenger, and he is weak in faith, and he is in grave danger of diseases of the heart and their consequences in this world and in the Hereafter, as Allaah says:
“Those among the Children of Israel who disbelieved were cursed by the tongue of Dawood (David) and ‘Eesa (Jesus), son of Maryam (Mary). That was because they disobeyed (Allaah and the Messengers) and were ever transgressing beyond bounds.
79. They used not to forbid one another from Al-Munkar (wrong, evildoing, sins, polytheism, disbelief) which they committed. Vile indeed was what they used to do” [al-Maa’idah 5:78-79]
And it is narrated in a saheeh report that the Messenger of Allaah (peace and blessings of Allaah be upon him) said: “Whoever among you sees an evil action, then let him change it with his hand [by taking action]; if he cannot, then with his tongue [by speaking out]; and if he cannot, then with his heart – and that is the weakest of faith.”
And he (peace and blessings of Allaah be upon him) said: If the people see an evil action and do not change it, soon Allaah will cause His punishment to encompass them all.” Narrated by Imam Ahmad with a saheeh isnaad from Abu Bakr al-Siddeeq (may Allaah be pleased with him).
There are many ahaadeeth on this topic; we ask Allaah to enable all the Muslims to undertake this great duty in the manner which pleases Him.”
Ref: Majmoo’ Fataawa al-Shaykh Ibn Baaz (6/504)
Posted by Abdul Kareem Ibn Ozzie