Allāh says, “The believers are those whose hearts tremble when Allāh is mentioned, whose faith is increased when His Signs are recited to them, who put their trust in their Lord, those who establish the prayer and give of what We have provided for them. They are the believers in truth. They have high ranks with their Lord and forgiveness and generous provision.” [al-Anfāl (8): 2-4]
Allāh describes the believers as having these qualities, qualities that cover the observance of the entire religion, its foundations and subsidiary rulings, the outer and the inner.
He describes them with such faith as manifests itself in their beliefs, statements and actions – both the inner and outer. He describes them as increasing in faith each time the verses of Allāh are recited, their fear and dread increasing each time Allāh is mentioned. These are people who truly and completely rely on Allāh, depend on Him in all their affairs, and relegate them to Him. Moreover, they establish the obligatory and optional prayers, perfecting them both inwardly and outwardly. They give zakāh and spend on what is obligatory upon them as well as recommended.
Whoever has these qualities, there is no more good left to be sought just as there is no more evil that remains to be feared. Such are “the believers in truth,” these are people who truly deserve to be called believers, these are people who have perfected faith inwardly and outwardly. Their reward? Forgiveness leading to the removal of all evil and matters to be wary of, high ranks with their Lord, and generous provision that no eye has seen, no ear has heard and no mind has imagined.
Allāh says, “The believers are successful. Those who are humble in their prayer, those who turn away from worthless talk, those who pay the zakāh, those who guard their private parts – except from their wives or those they own as slaves, in which case they are not blameworthy; but those who desire more than that are people who have gone beyond the limits – those who honour their trusts and contracts and those who safeguard their prayers. Such people are the inheritors who will inherit al-Firdaws, remaining in it timelessly, forever.” [al-Muʾminūn (23): 1-11]
Allāh explains that faith covers everything mentioned in these verses, first by stating that the believers are successful, then by describing their qualities with His words, “those who are humble in their prayer…”
Therefore, the person who observes these mannerisms is a believer in truth. The general sense of these verses is one of establishing the obligations, both outwardly and inwardly, as well as avoiding the prohibited and detested matters. Through completing faith, one deserves to inherit al-Firdaws which is the highest garden of Paradise as a fitting reward for perfecting the loftiest objective in this world.