Is it necessary in order to denounce evil that it be removed completely, or is it sufficient to reduce it
Question

                If I want to denounce some evil, but we cannot remove it completely but we are able to reduce it, should we get involved for that purpose? Or should we say that we have to either remove it completely or not do anything at all?
Praise be to Allah. 
          The correct view is that we have to remove evil as much 
          as we can. Our efforts should be aimed primarily at removing it completely. 
          If we are not able to do that, but we can reduce it or reduce some of 
          its effects, then the basic principles of sharee’ah dictate that we 
          should do that, especially since we are living at a time when he evildoershave 
          the upper hand and those who seek to enjoin what is good and forbid 
          what is evil and to call people to Allaah are unable to achieve all 
          that they want to do. We can at least reduce the effects of evil; if 
          there is something that is difficult to remove, this is no excuse for 
          not doing what we can. We should not give up altogether on something 
          of which we can only do a part. Allaah does not burden any soul beyond 
          its scope, but we have to be certain about the basic principle in this 
          matter, which is that the daa’iyah (caller) who wants to enjoin what 
          is good and forbid what is evil should not be content with a partial 
          solution or accept a reduction of the evil when it is possible to eradicate 
          it completely. 
 
          Often those who enjoin what is good and forbid what is 
          evil are content to reduce the evil without striving to remove it… Like 
          the one who tells a woman who is showing a lot of her charms to non-mahram 
          men to cover all of that apart from the hands and face, even though 
          he is able to tell her to observe complete hijaab.
 
           And like the one who passes by someone who is playing 
          singing and music loud, and he tells him to turn down the sound of that 
          evil. 
 
          And like the one who is asked to teach women or girls, 
          and he sets down the condition that they should wear hijaab and not 
          speak in soft voices, even though he is able to demand that a screen 
          be placed between him and them so that they can hear his voice without 
          him seeing them. 
 
          Among the evidence concerning this matter that is mentioned 
          in the Qur’aan is what Moosa (peace be upon him) did with the calf which 
          the Children of Israel worshipped and were devoted to. He said: 
 
          “We will certainly burn it, and scatter its particles 
          in the sea”
 
          [Ta-Ha 20:97 – interpretation of the meaning]
 
          The Sunnah is what the Prophet 
          
          (peace and blessings of Allaah be upon him) did with the masjid al-diraar 
          (a mosque built by way of harming and diselief, cf. al-Tawbah 9:107), 
          which had been built by the hypocrites. He ordered that it should be 
          burned after being detsroyed. 
 
          Al-Bukhaari and others narrated from the hadeeth of Ibn 
          Mas’ood (may Allaah be pleased with him) that he said, “The Prophet 
          
          (peace and blessings of Allaah be upon him) entered Makkah on the day 
          of the Conquest, and there were three hundred and sixty idols around 
          the Ka’bah. He started hitting them with a stick that he had in his 
          hand, saying, ‘Truth has come and falsehood has vanished. Truth has 
          come and faslehood can neither create nor resurrect anything.” (Narrated 
          by al-Bukhaari). 
 
          Another example was narrated by al-Bukhaari in his Saheeh, 
          in the hadeeth of Jareer ibn ‘Abd-Allaah al-Bajali (may Allaah be pleased 
          with him) who said, “The Messenger of Allaah 
          
          (peace and blessings of Allaah be upon him) said to me, ‘Won't you relieve 
          me from Dhul-Khalasah?' I replied, 'Yes, (I will relieveyou).' So I went along with one hundred and fiftycavalry from the tribe of Ahmas who were skillful in ridinghorses. I used not to sit firmly on a horse, so I informedthe Prophet 
          
          (peace and blessings of Allaah be upon him) of that, and he hit my chest 
          with hishand till I saw the marks of his hand 
          on my chest andhe said, ‘O Allah! Make him firm 
          and one who guidesothers and is guided (on the 
          right path).' Since then Ihave never fallen 
          from a horse. Dhul-l-Khalasah was ahouse in 
          Yemen belonging to the tribe of Jath’am andBajeelah, and in it there were idols which were worshipped, and 
          it was called al-ka'bah." Jareer wentthere, 
          burnt it with fire and destroyed it.  
 
          When Jareer came to Yemen, there was a man who used to 
          tell fortunes and give good omens by casting arrows of divination. 
          Someone said to him, "The 
          messenger of the Messenger of Allaah 
          
          (peace and blessings of Allaah be upon him) is here, is present here 
          and if he should get hold of you, hewill chop 
          off your head." One day while the man was usingthem (i.e. arrows of divination), Jareer stopped there andsaid to him, "Break them (i.e. the arrows) and testifythat None has the right to be worshipped except Allaah, or else 
          I will chop off your head." So the man brokethose 
          arrows and testified that none has the right to be 
          worshipped except Allah. Then Jareer sent a man calledAbu Artaa’ah from the tribe of Ahmas to the Prophet 
          
          (peace and blessings of Allaah be upon him) toconvey 
          the good news (that Dhul-Khalasah had been destroyed). So when the messenger reached the Prophet 
          
          (peace and blessings of Allaah be upon him), he said, "O 
          Messenger of Allaah! By Him Who sent you with the Truth, I did not come 
          until I left it like a scabby camel." Thenthe 
          Prophet 
          
          (peace and blessings of Allaah be upon him)  said, “May 
          Allaah bless the horses of Ahmas and their men,”five 
          times.
 
          The relevant points in this hadeeth are two: what he 
          did to Dhul-Khalasah, and how he dealt with the one who used arrows 
          for fortune-telling etc. 
 
          And it says in al-Fath: “This hadeeth indicates 
          that it is prescribed in Islam to remove things by which people may 
          be tempted, be they buildings or other things, even if it is a person, 
          an animal or an inanimate object.” (8/73) 
 
          Another example is when Khaalid ibn al-Waleed (may Allaah 
          be pleased with him) was sent to al-‘Uzza and he cut down the three 
          gum-acacia trees and destroyed the house. When he told him what he had 
          done, the Prophet 
          
          (peace and blessings of Allaah be upon him) told him that he had not 
          done anything. He told him to go back and find that naked woman with 
          dishevelled hair who was pouring dust on her head, and so he went back 
          and killed her with a sword… When he came back to the Prophet 
          
          (peace and blessings of Allaah be upon him) and told him, the Messenger 
          of Allaah 
          
          (peace and blessings of Allaah be upon him) said, “That was al-‘Uzza” 
          (Zaad al-Ma’aad, 3/414). 
 
          It was narrated from one of the salaf that he passed 
          by two boys who were playing in a hole in which there were pebbles with 
          which they were playing. He blocked it up and forbade them to go there. 
          Tafseer al-Qurtubi, 8/340 
 
          But if the one who is enjoing good and forbidding evil 
          is unable to remove the evil completely, then he should strive to reduce 
          it as much as possible. 
 
          Ibn al-Qayyim (may Allaah have mercy on him) said, when 
          mentioning some of the lessons learned from the battle of Tabook, “We 
          also learn that places of sin in which Allaah and His Messenger are 
          disobeyed are to be burned and destroyed, as the Messenger of Allaah 
          
          (peace and blessings of Allaah be upon him) burned the masjid al-diraar 
          (a mosque built by way of harming and diselief, cf. al-Tawbah 9:107) 
          and commanded that it should be destroyed. This was a mosque in which 
          prayers were offered and the name of Allaah was mentioned, but it had 
          been built to cause harm and divide the believers, and as a refuge for 
          the hypocrites. In the case of places of this type, the ruler  
          has to put a stop to it, either by destroying it and burning it, or 
          by changing its appearance and using it for a different purpose. If 
          this was the case concerning a mosque built for harming and disbelief, 
          then places of shirk whose cutodians promote taking those inside them 
          as rivals to Allaah are even more deserving of being destroyed. The 
          same applies to places of sin and immorality, such as bars and places 
          of evil. ‘Umar ibn al-Khattaab burned an entire village in which wine 
          was sold, and he burned the shop of Ruwayshid al-Thaqafi and called 
          him Fuwaysiq. [Ruwayshid comes from a word meaning “guided” and Fuwaysiq 
          comes from a word meaning “immoral.” – Translator].  And he burned 
          the fortress of Sa’d in which he was hiding away from people. The Messenger 
          of Allaah 
          
          (peace and blessings of Allaah be upon him) wanted to burn down the 
          houses of those who did not attend prayers in congregation or Jumu’ah 
          prayers; the only thing that kept him from doing that was the woman 
          and children who were not obliged to attend these prayers, as he told 
          us. (Zaad al-Ma’aad, 3/571-572)