عَن أبي أَيُّوب قَالَ: كُنَّا عِنْدَ النَّبِيِّ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ فَقُرِّبَ طَعَامٌ فَلَمْ أَرَ طَعَامًا كَانَ أَعْظَمَ بَرَكَةً مِنْهُ أَوَّلَ مَا أَكَلْنَا وَلَا أَقَلَّ بَرَكَةً فِي آخِرِهِ قُلْنَا: يَا رَسُولَ اللَّهِ كَيْفَ هَذَا؟ قَالَ: «إِنَّا ذَكَرْنَا اسْمَ اللَّهِ عَلَيْهِ حِينَ أَكَلْنَا ثُمَّ قَعَدَ مَنْ أَكَلَ وَلَمْ يُسَمِّ اللَّهَ فَأَكَلَ مَعَهُ الشَّيْطَانُ» . رَوَاهُ فِي شرح السّنة

Sa‘d said

When I was ill the Prophet came to visit me, and putting his hand between my nipples so that I felt its coolness on my heart, he said, “You are suffering from a heart disease. Go to al-Harith b. Kalada who belongs to Thaqif, for he practices medicine, and get him to take seven of the 'ajwa dates of Medina and pound them together with their stones, then administer them to you.” Abu Dawud transmitted it.