An Ayah that is better than a thousand Ayat

Messenger of Allah (pbuh) used to recite Al-Musabbihat before he went to sleep, saying In them there is an Ayah that is better than a thousand Ayat. 
[Abu Dawud, At-Tirmidhi and An-Nasa'i collected this Hadith.]

He is Al-Awwal and Al-Akhir, Az-Zahir and Al-Bat in. And He is the All-Knower of everything

 [ Quran 57:3 ]

 This is the Ayah indicated in the Hadith of ` Irbad bin Sariyah that is better than a thousand Ayat. Abu Dawud recorded that Abu Zamil said, "I mentioned to Ibn ` Abbas that I felt something in my heart. He said, ` Doubts' and then laughed. Next, he said,`No one can escape this. Allah the Exalted stated 'So if you are in doubt concerning that which We have revealed to you, then ask those who are reading the Book before you. Verily, the truth has come to you from your Lord.' [ Quran 10:94 ]
He then said to me, `When you feel any of this in your heart, recite,  (He is Al-Awwal and Al-Akhir, Az-Zahir and Al-Bat in. And He is the All-Knower of everything. )
Al-Bukhari said, "Yahya said,` Az-Zahir: knowing all things, Al-Bat in: knowing all things'
Our Shaykh Al-Haf iz Al-Mizzi said, "Yahya is Ibn Ziyad Al-Farra', who authored a book entitled Ma`ani Al-Qur'an."
 There are Hadiths mentioned about this. Among them, Imam Ahmad recorded that Abu Hurayrah said that  the Messenger of Allah (pbuh) would recite this supplication while going to bed,
(O Allah, Lord of the seven heavens and Lord of the Magnificent Throne! Our Lord, and the Lord
of everything, Revealer of the Tawrah, the Injil and the Furqan, the Splitter of the grain of
corn and the date stone! I seek refuge with You from the evil of everything whose forhead You
have control over. O Allah! You are Al-Awwal, nothing is before You; Al-Akhir, nothing is after
You; Az-Zahir, nothing is above You; and Al-Bat in, nothing is below You. Remove the burden of
debt from us and free us from poverty.)

 [ extract from Tafsir Ibn Katheer ]