Sayyiduna Bilal bin Rabah (may Allah be pleased with him) says: I came to the Messenger of Allah (peace and blessings be upon him) to inform him about the prayer, while he intended to fast. So the Messenger of Allah (peace and blessings be upon him) had a bowl brought, drank from it himself, and gave me to drink as well. After that, the Messenger of Allah (peace and blessings be upon him) proceeded towards the mosque for prayer and began to pray without performing ablution, while he intended to fast.
Hadith Referenceالفتح الربانی / كتاب الصيام / 3735
Hadith Gradingمحدثین:صحیح
Hadith Takhrij«رجاله ثقات رجال الشيخين، الا ان عبد الله بن معقل المزني لايعرف له سماع من بلال۔ اخرجه الطبراني: 1082، (انظر مسند أحمد ترقيم الرسالة: 23889 ترقیم بيت الأفكار الدولية: 24386»
Brief Explanation
Benefits: … Performing prayer without ablution (wudu) was the personal understanding of Sayyiduna Bilal radi Allahu anhu; otherwise, either the Prophet sallallahu alayhi wa sallam had performed ablution before sleeping—while his ablution was not affected by sleep—or it is possible that the Prophet sallallahu alayhi wa sallam performed ablution after waking up, but Sayyiduna Bilal radi Allahu anhu was not aware of it. There is no doubt whatsoever that there are extremely clear rulings related to the beginning and end of fasting, and it is in light of these that such ahadith will be interpreted. For example, it is possible to interpret this hadith as follows: the Prophet sallallahu alayhi wa sallam intended to fast, but was unable to wake up on time; therefore, when he opened his eyes, since the time had ended, he sallallahu alayhi wa sallam, benefiting from this concession, ate a brief pre-dawn meal (suhoor), the concession which has been mentioned in hadith number (3737) and its benefits. And Allah knows best what is correct.