The Messenger of Allah ﷺ as saying: When one of you gets up at night, he should begin the prayer with two short rak'ahs. (Using translation from Abū Dāʾūd 1323)
قَالَ رَسُولُ اللهِ ﷺ إِذَا قَامَ أَحَدُكُمْ يُصَلِّي مِنَ اللَّيْلِ فَلْيَبْدَأْ بِرَكْعَتَيْنِ خَفِيفَتَيْنِ