It was narrated from Abu Hurairah that the Prophet (ﷺ) said:“If anyone of you is invited to eat when he is fasting, let him say: ‘I am fasting.’”
Hadith No. 1750
Sunan Ibn Majah
Gradings:
Al-Albani:
Sahih
Muhammad Fouad Abd al-Baqi:
Sahih
Shuaib Al Arnaut:
Sahih
Zubair Ali Zai:
Sahih Muslim