Reference: Sharh ‘Umdatil-Fiqh – Tape No.9, Question No.41
Question: Some [people] infer that it is permissible to verbalise the intention [using as evidence] the Prophet’s ﷺ words “I am fasting” – when he did not find anything to eat?
Response: This is [simply] the Prophet ﷺ informing that he is fasting, when he asked for food and was told there is nothing [to eat]. So he is just informing [those around him] that he is fasting, and this [words do] not [constitute] an intention.