كان إذا أفطر عند قوم قال: [أفطر عندكم الصائمون وصلت عليكم الملائكة]
It was the practice of the Prophet (peace and blessings be upon him):
"When he (peace and blessings be upon him) broke his fast with a people, he would say: 'Those fasting have broken their fast with you, and the angels have sent blessings upon you.'"
Hadith Referenceصحیح الجامع الصغیر / حرف الكاف / 4679
Hadith Gradingالألبانی:صحيح
Hadith Takhrij[طب] عن ابن الزبير. آداب الزفاف ص ٨٥: الخطيب.