Dogs are Impure and Develish says Islam

It is not permissible for a Muslim to keep a dog, unless he needs this dog for hunting, guarding livestock or guarding crops.

  

You might be wondering from where did this come.... But no matter how wonder stuck you are or how many examples that might comes in your mind of people of muslim faith having Dogs  or how absurd it might sound to you, but this what is stated in their scripturerules:

Al-Bukhaari (2145) narrated that Abu Hurayrah said: “Whoever keeps a dog, a qiraat from his good deeds will be deducted every day, except a dog for farming or herding livestock.” 

Muslim (2978) narrated from Abu Hurayrah said: “Whoever keeps a dog that is not a dog for hunting, herding livestock or farming, two qiraats will be deducted from his reward each day.” 

Muslim (2943) narrated from ‘Abd-Allaah ibn ‘Umar said: “Whoever keeps a dog, except a dog for herding livestock or a dog for hunting, a qiraat will be deducted from his good deeds each day.”

‘Abd-Allaah said: Abu Hurayrah said: Or a dog for farming. 

Ibn ‘Abd al-Barr said: This hadeeth shows that it is permissible to keep a dog for hunting and herding livestock, and also for farming. 

So from a Hindu prospective by closely observing the above scriptures, with our limitted understanding, it can be stated that a muslim can have a dog only for purpose and that purpose can be anything(which are allowed by scriptures) but not love.You cannot have a dog just because you love a dog, "love for the loves sake" this phliosophy of ours are missing in the above scriptures .So in plain language it can be said that if you have any work to be done use it or else throw it.If any one asks why?? Because it is KAFARIC attitute to love a dog. The reason that one should avoid dogs are being stated as 

Ibn Maajah (3640) narrated from ‘Ali ibn Abi Taalib said: “The angels do not enter a house in which there is a dog or an image.” 

Now the Islamic scholars after many brain storming sessions and exhausting its superior intellect have managed solved the most muddling issue the world faces, How many qiraat(kind of currency of good things you do) are deducted? 

 The scholars differed as to how to reconcile between the reports which speak of one qiraat being deducted and those which speak of two qiraats being deducted. 

It was said that two qiraats will be deducted if the dog is more harmful and one qiraat will be deducted if it is less so. 

And it was said that that at first the Prophet (peace and blessings of Allaah be upon him) said that one qiraat would be deducted, then the punishment was increased after that, so he said that two qiraats would be deducted in order to put people off from keeping dogs even more. 

The qiraat is an amount that is known to Allaah, may He be exalted, and what is meant is that some of the reward for a person’s good deeds will be deducted. 

See Sharh Muslim by al-Nawawi, 10/342; Fath al-Baari, 5/9 

Shaykh Ibn ‘Uthaymeen said in Sharh Riyaadh al-Saaliheen, 4/241: 

With regard to keeping dogs, this is haraam and is in fact a major sin, because the one who keeps a dog, except those for which an exception has been made, will have two qiraats deducted from his reward every day.

Who keeps a Dog and the nature of its impurity is stated as:

It is by the wisdom of Allaah that like calls to like and evil calls to evil. It is said that the kaafirs, Jews, Christians and communists in the east and the west all keep dogs, Allaah forbid. Each one takes his dog with him and cleans it every day with soap and other cleansing agents. But even if he were to clean it with the water of all the seas in the world and all the soap in the world, it would never become pure! Because its impurity is inherent, and inherent impurity cannot be cleansed except by destroying it and erasing it altogether. 

Source:Islamqa