COMMENTARY on 57:19
A. Yusuf Ali:

Translation:
And those who believe in Allah and His messengersthey are the Sincere 5299 (lovers of Truth), and the witnesses (who testify), 5300 in the eyes of their Lord: They shall have their Reward and their Light. 5301 But those who reject Allah and deny Our Signs,- they are the Companions of Hell-Fire.
Commentary:

5299  Cf. 4:69, and n. 586. The four categories there mentioned as constituting the beautiful Fellowship of Faith are: the Prophets who teach, the Sincere Lovers of Truth, the Witnesses who testify, and the Righteous who do good. Of these, the prophets or messengers have already been mentioned in this verse. The Righteous who do good are mentioned as the men and women given over to deeds of charity in verse 18.

5300  The Witnesses are not only Martyrs, but all those who carry the Banner of Truth against all odds and in all positions of danger, whether by pen or speech, or deed or counsel.

5301  Note that these two are specially high degrees in the spiritual kingdom, just short of Prophethood. For they have not only their reward in the spiritual Kingdom of Allah , like those who practise charity (verse 18 above), but they themselves become sources of light and leading.

 

Muhammad Asad:

Translation:
For, they who have attained to faith in God and His Apostle - it is they, they who uphold the truth, and they who bear witness [thereto] before God: 28 [and so] they shall have their reward and their light! But as for those who are bent on denying the truth and on giving the lie to Our messages - it is they who are destined for the blazing fire!
Commentary:
28  I.e., by their readiness for any sacrifice.