Question
What is the authenticity of the following du’a?
Whoever says ‘Allah is the Greatest, the amount of even and odd (prayer), (the amount) of Allah’s complete, pure and blessed words. There is no god except Allah’, thrice after every salah and when he goes to sleep, it will be a means of light for him in his grave ,light on the plain of resurrection and light on the Sirat (bridge) until they (this du’a) see him into Jannah.
The Arabic text of the du’a is as follows:
(x3) الله أكبر كبيرا عدد الشفع، والوتر، وكلمات الله التامات الطيبات المباركات
(x3) لا إله إلا الله