Al-Ahzaab 33:23

Among the believers there are men who have been true to their pledge to Allah. Some of them have fulfilled their pledge[22], and others are still waiting[23], and they have not changed in the least[24].

[22] i.e., have been martyred or died in the way of Allah.
[23] i.e., waiting to be martyred for the sake of Allah.
[24] Unlike the hypocrites who have betrayed their pledges.

Among the believers are men true to what they promised Allāh. Among them is he who has fulfilled his vow [to the death], and among them is he who awaits [his chance]. And they did not alter [the terms of their commitment] by any alteration -

23. Among the believers are men who have been true to their covenant with Allâh [i.e. they have gone out for Jihâd (holy fighting), and showed not their backs to the disbelievers]; of them some have fulfilled their obligations (i.e. have been martyred); and some of them are still waiting, but they have never changed [i.e. they never proved treacherous to their covenant which they concluded with Allâh] in the least.[5]

[5] (V.33:23) Narrated Anas رضي الله عنه: My uncle Anas bin An-Nadr was absent from the battle of Badr. He said, "O Allâh’s Messenger (صلى الله عليه وسلم)! I was absent from the first battle you fought against the pagans. (By Allah) if Allah gives me a chance to fight the pagans, no doubt, Allah will see how (bravely) I will fight." On the day of Uhud when the Muslims turned their backs and fled, he said, "O Allah! I apologise to You for what these (i.e. his companions) have done, and I denounce what these (i.e. the pagans) have done." Then he advanced and Sa‘d bin Mu‘âdh met him. He said, "O Sa‘d bin Mu‘âdh! By the Lord of An-Nadr, Paradise! I am smelling its aroma coming from before (the mountain of) Uhud," Later on, Sa‘d said, "O Allah’s Messenger! I cannot achieve or do what he (i.e. Anas bin An-Nadr) did. We found more than eighty wounds by swords and arrows on his body. We found him dead and his body mutilated so badly that none except his sister could recognise him by his fingers." We used to think that the following Verse was revealed concerning him and other men of his sort: "Among the believers are men who have been true to their covenant with Allah."(V.33:23).
His sister Ar-Rubaiyi‘ broke a front tooth of a woman and Allâh’s Messenger صلى الله عليه وسلم ordered for retaliation. On that Anas bin An-Nadr, said, "O Allâh’s Messenger! By Him Who has sent you with the truth, my sister’s tooth shall not be broken, then the opponents of Anas’s sister accepted the compensation and gave up the claim of retaliation. So Allâh’s Messenger صلى الله عليه وسلم said, "There are some people amongst Allâh’s slaves whose oaths are fulfilled by Allah when they take them." (Sahih Al-Bukhari, Vol.4, Hadîth No.61).

Of the believers are men who are true to that which they covenanted with Allah. Some of them have paid their vow by death (in battle), and some of them still are waiting; and they have not altered in the least;