It is narrated from Sayyiduna Ibn Abbas (may Allah be pleased with them both) that the Prophet (peace and blessings be upon him) said: "If any Muslim visits a sick person whose time of death has not come near and says seven times, 'I ask Allah, the Lord of the Magnificent Throne, to grant you healing,' then Allah Almighty grants him well-being."
Hadith Referenceمسند احمد / ومن مسند بني هاشم / 3298
Hadith Gradingحکم دارالسلام:حديث صحيح، حجاج بن أرطاة مدلس وقد عنعن، لكنه متابع