Those who believe in what has been revealed to you
And those who believe in what has been revealed to you, [O Muhammad], and what was revealed before you, and of the Hereafter they are certain. Some qualities of mutqeen are described in this verse of the Surat Albaqoroh.Those who believe on the Divine books including Quran and the scriptures revealed before Quran and on the Day of judgment, life after death.
