It is narrated from Sayyiduna Abu Hurayrah (may Allah be pleased with him) that the Prophet (peace and blessings be upon him) said: "Whoever recites 'Say: He is Allah, the One' ten times, a palace will be built for him in Paradise; whoever recites it twenty times, two palaces will be built for him; and whoever recites it thirty times, three palaces will be built for him."
Imam al-Tabarani (may Allah have mercy on him) said: "No one narrated this hadith from Zuhrah bin Ma'bad with a connected chain except Khalid bin Humayd, and Hani' bin al-Mutawakkil is alone in narrating it."
Hadith Referenceالمعجم الأوسط / باب الألف / 281
Hadith Gradingمحدثین:إسناده ضعيف لضعف هانئ بن المتوكل
Hadith Takhrij«قال الهيثمي: فيه هانئ بن المتوكل وهو ضعيف «مجمع الزوائد ومنبع الفوائد، ج 7، ص 145»»