Sayyiduna Abu Musa al-Ash'ari (may Allah be pleased with him) reports this saying of the Prophet (peace and blessings be upon him): "Whoever sends blessings upon me once, Allah Almighty, in return, sends ten mercies upon him."
Al-Tabarani recorded it; its chain contains Hafs bin Sulayman al-Qari, whom Waki' and others declared thiqah (trustworthy), while the majority declared him da'if (weak); the remaining narrators of this narration are thiqat (trustworthy).
Hadith Referenceمجمع الزوائد ومنبع الفوائد / كتاب الأدعية / 17302