Abu al-Hakam (may Allah have mercy on him) said: I heard Sayyiduna Abdullah bin Umar (may Allah be pleased with him) narrate that he (peace and blessings be upon him) said: "Whoever keeps in his house a dog other than a dog for guarding crops, a dog for guarding sheep or a hunting dog, one qirat will be deducted from his good deeds every day."
Hadith Referenceالسنن الكبرى للبيهقي / كتاب البيوع / 11029