Is it permissible in Islam to keep dogs?
The jurists agreed that it is not permitted to keep a dog unless it is for a purpose, like hunting or guarding property or other uses that are not contrary to the Shari`ah.
The Prophet (peace and blessing of Allah be upon him) said: "Whoever keeps a dog, except a dog for herding, hunting or farming, his reward will decrease by one qirat every day." (Narrated by Muslim, 2948)
As far as keeping a dog to guard the house is concerned, Ibn Qudamah said: "It is not permitted, according to the most sound opinion." (Al-Mawsu`ah Al-Fiqhiyyah, 35/124)
Are dogs impure?
As regards the impurity of the dog, the Shafi`i and Hanbali scholars say that the whole dog is essentially impure . Some scholars say that any liquid excreted by the dog is impure (not the dog itself).
The saliva of the dog is extremely impure , because the Prophet (peace and blessings of Allah be upon him) said: "If a dog licks the vessel of any one of you, let him throw away whatever was in it and wash it seven times." (Narrated by Muslim, no. 418)
Abu Hurayrah (may Allah be pleased with him) reported that the Messenger of Allah (peace and blessings of Allah be upon him) said: "The way to purify the vessel of any one of you if a dog has licked it is to wash it seven times, the first time with earth." (Narrated by Muslim, no. 420)
We must ensure that Muslims continue to be averse to dogs, even in the midst of what the non-Muslims are used to doing, and what some Muslims have adopted of their habits.
And Allah knows best.