Suppose someone resolves in the night of Ramadan to fast the following day and then sleeps. They do not recite any separate declaration at dawn.
The nighttime resolve counts as intention. Waking at dawn to repeat a formula is not a condition; the other fasting conditions, including abstention from true dawn, must still be satisfied.
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Kitab al-Sawm: Categories of Fasting and Rules of Intention
Suppose someone resolves in the night of Ramadan to fast the following day and then sleeps. They do not recite any separate declaration at dawn.
The nighttime resolve counts as intention. Waking at dawn to repeat a formula is not a condition; the other fasting conditions, including abstention from true dawn, must still be satisfied.