power of sincere (Ikhlas) : Al Mulk(2) that He may try which of you is best in deed

recently I bought a book on power of 'ikhlas'.

Inside the book written a story of 3 people in a cave that pray to Allah of the 'Ikhlas'
good-deed they have done to open the cave's door. ( Remind me of Ustazah Hanan)


Al-Mulk (2):

"He Who created Death and Life, that He may try which of you is best in deed: and He is the Exalted in Might, Oft-Forgiving― (2) "




In the book, also mention surah Al Mulk ayat 2 that reminds me to this talk

http://read-quran-online.blogspot.com/2011/06/read-quran-surah-al-mulk-ayah-2.html


http://read-quran-online.blogspot.com/2009/11/quranic-verses-surat-mulk.html