The Messenger of Allah ﷺ said, "Whoever says, 'There is no god but Allah alone, with no partner. To Him belongs the dominion and to Him belongs all praise. He gives life and causes death, and He has power over all things,' ten times after the Maghrib prayer, Allah will send guardians to protect him from Satan until morning, and Allah will record for him ten good deeds that ensure reward, wipe away from him ten ruinous sins, and it will be equivalent for him to freeing ten believing slaves."
حدثنا قتيبة حدثنا الليث عن الجلاح أبي كثير عن أبي عبد الرحمن الحبلي
قال رسول الله ﷺ من قال لا إله إلا الله وحده لا شريك له له الملك وله الحمد يحيي ويميت وهو على كل شيء قدير عشر مرات على إثر المغرب بعث الله مسلحة يحفظونه من الشيطان حتى يصبح وكتب الله له بها عشر حسنات موجبات ومحا عنه عشر سيئات موبقات وكانت له بعدل عشر رقاب مؤمنات
[Hasan]References Nasai also narrated it in Amal al-Yawm wal-Layla, no. 577 (duplicate), from Qutayba, with the same wording.Umara bin Shabib heard it from a man among the Ansar, as noted in Amal al-Yawm wal-Layla, no. 578.