Supplication by one fasting when food is presented and he does not break his fast

The Messenger of Allah ﷺ said: "When any of you is invited, let him accept the invitation. If he is fasting, let him pray; and if he is not fasting, let him eat" [Muslim 3520].

Here "let him pray" means "let him supplicate" — i.e., invoke blessings upon those who have invited him and upon all who are gathered. Some scholars, however, have held that it refers to performing a [voluntary] prayer in the usual sense.