Reference : Hisn al-Muslim 71

﴿اللّهُ لاَ إِلَـهَ إِلاَّ هُوَ الْحَيُّ الْقَيُّومُ
لاَ تَأْخُذُهُ سِنَةٌ وَلاَ نَوْمٌ
لَّهُ مَا فِي السَّمَاوَاتِ وَمَا فِي الأَرْضِ
مَن ذَا الَّذِي يَشْفَعُ عِنْدَهُ إِلاَّ بِإِذْنِهِ
يَعْلَمُ مَا بَيْنَ أَيْدِيهِمْ وَمَا خَلْفَهُمْ
وَلاَ يُحِيطُونَ بِشَيْءٍ مِّنْ عِلْمِهِ إِلاَّ بِمَا شَاء
وَسِعَ كُرْسِيُّهُ السَّمَاوَاتِ وَالأَرْضَ
وَلاَ يَؤُودُهُ حِفْظُهُمَا
وَهُوَ الْعَلِيُّ الْعَظِيمُ﴾
عقب كل صلاة
Allāhu lā ilāha illā huwa ‘l-Ḥayyul-Qayyūm, 
lā ta'khudhuhu sinatun wa lā nawm, 
lahu mā fis-samāwāti wa mā fil-ardh, 
man dhal-ladhī yashfa`u `indahu illā bi'idhnih, 
ya`lamu mā bayna 'aydīhim wa mā khalfahum, 
wa lā yuḥītūna bishay'im-min `ilmihi illā bimā shā'a, 
wasi `a kursiyyuhus-samāwāti wal-ardh, 
wa lā ya'ūduhu hifẓuhumā, 
wa huwal-`Aliyyu ‘l-`Aẓīm.


Allah! There is none worthy of worship but He, the Ever-Living, the One Who sustains and protects all that exists.
Neither slumber nor sleep overtakes Him.
To Him belongs whatever is in the heavens and whatever is on the earth.
Who is he that can intercede with Him except with His Permission?
He knows what happens to them in this world, and what will happen to them in the Hereafter.
And they will never compass anything of His Knowledge except that which He wills.
His Throne extends over the heavens and the earth,
and He feels no fatigue in guarding and preserving them.
And He is the Most High, the Most Great. (Recite in Arabic after each prayer.)

Reference:
An-Nasa'i, 'Amalul-Yawm wal-Laylah (Hadith no. 100), also Ibn As-Sunni (no. 
121). See also Al-Albani, Sahihul-Jami' As-Saghir 5/339 and 
Silsilatul-Ahadith As-Sahihah 2/697 (no. 972).

Chapter: After salam