There is Hadith in Sahih Muslim, Tirmidhi and Sahih Ibn Hibban from Sayyiduna Abu Malik (radiyallahu ‘anhu) that states: ‘Subhanallah and alhamdulillah fills what is between Heaven and Earth.’
1. What is meaning fill the space between Heaven and Earth?
2. Does it mean that reward of reciting these words, a person will get reward which is equivalent to the space between Heaven and Earth? Please explain the meaning
Several Hadith commentators have explained that this refers to the reward for its recital filling the space between the heavens and the earth.
(Sharhun Nawawi ‘ala Sahih Muslim, Hadith: 533, Mirqatul Mafatih, Hadith: 281 and Dalilul Falihin, Hadith: 251, vol.1 pg.149).
This illustrates the value of these phrases in the court of Allah. Some Hadiths have labelled these [among others] as the most beloved of phrases to Allah.
In fact, this is the dhikr/wird [often repeated words] of everything between the heavens and the earth. (Surah Isra, verse: 44). Some commentators have drawn this link for the stated reward in the above Hadith.
(Refer: Dalilul Falihin, Hadith: 251)
And Allah Ta’ala Knows best.
Answered by: Moulana Muhammad Abasoomar