Assalamualaikum warahmatullahi wabarakatuh.
DU'A BEFORE SLEEPING
اللَّهُمَّ بِسْمِكَ اَمُوْتُ وَاَحْيَا
Allahumma bismika amu-tu waahya-
"Oh ALLAH, with Your Name i die and i live."
***We also can recite Surah Al-Ikhlas, Surah Al-Falaq, and Surah Annas for 3 times to prevent us from evil.
(Surah Al-Ikhlas, Surah Al-Falaq and Surah Annas)
Let's practice it together.
Allahu'alam.
Wassalam.
