Sunan at-Tirmithiy كتاب الصلاة باب ما جاء فى القراءة فى صلاة العشاء
The Prophet, peace and blessings of God be upon him, said, "Do the odd-numbered prayer (1) before it dawns." Footnotes: (1): The voluntary night prayer that ends a person's worship for that day, and is performed in an odd number of prayer units (one unit, three units, etc.) Click on ḥadīth to read more