It is narrated from Sayyiduna Tamim al-Dari (may Allah be pleased with him) that the Messenger of Allah (peace and blessings be upon him) said: "Whoever bears witness ten times that there is no deity worthy of worship except Allah, One, Unique, Self-Sufficient, who has taken neither wife nor child, and to whom no one is equal, Allah records for him forty thousand good deeds."
Hadith Referenceالمعجم الكبير للطبراني / باب التاء / 1265