He (the Holy Prophet) loved (that action) which one keeps on doing regularly. I said (to 'A'isha): When did he pray (at night)? She replied: When he heard the cock crow, he got up and observed prayer.
The Book of Prayer - Travellers
Sahih Muslim 741
Hadith Commentary
This noble hadith from the Mother of the Believers, 'A'isha (may Allah be pleased with her), reveals two profound principles of worship. Firstly, the Prophet (peace be upon him) favored consistent acts of devotion, even if small, over sporadic lengthy worship. This embodies the Quranic principle of "the most beloved deeds to Allah are the most constant, even if little."
Secondly, his timing of prayer at the cock's crow signifies the excellence of the last third of the night, when Allah descends to the lowest heaven and asks: "Who is asking Me so I may give him?" This time is particularly blessed for seeking forgiveness and drawing near to the Almighty.
The wisdom in using the cock's crow as an indicator teaches us to observe Allah's signs in creation. Just as the rooster announces the approaching dawn, the believer's heart should awaken to divine remembrance. This practice combines regularity with optimal timing - the essence of accepted worship.
Legal Rulings
The night prayer (Tahajjud) is a confirmed Sunnah (Sunnah Mu'akkadah) for the Prophet and recommended (Mustahabb) for his ummah.
Prayer during the last third of the night holds special merit, though night prayer is permissible anytime after Isha until Fajr.
Consistency in voluntary acts is superior to occasional lengthy worship that cannot be maintained.