Sayyiduna Abdullah bin Umar (may Allah be pleased with them both) narrates: A man addressed the Prophet Muhammad (peace be upon him) in a loud voice and asked: What do you command us regarding how we should perform prayer at night? The Prophet Muhammad (peace be upon him) said: Perform the night prayer in sets of two rak‘ahs, and when you fear that dawn is near, then perform one rak‘ah; in this way, you will make your night prayer odd-numbered.
Hadith Referenceصحیح ابن حبان / كتاب الصلاة / 2622
Hadith Gradingفضيلة الشيخ الإمام محمد ناصر الدين الألبانيصحيح - «الروض النضير» (519)، «صحيح أبي داود» (1197): ق.فضيلة الشيخ العلّامة شُعيب الأرناؤوطإسناده صحيح على شرط البخاري