[ al-Ḥarb is interpreted in two ways:
1. By al-Ḥarb, kufr (disbelief) is intended; as in the following verses:
O you who have believed, fear Allah and give up what remains [due to you] of interest, if you should be believers. But if you do not, then be informed of a war from Allah and His Messenger. (al-Baqara 2:278–279)
Here, by ḥarb, kufr is intended.
The recompense of those who wage ḥarb (i.e., those who commit kufr against Allah and His Messenger) is only... (al-Māʾida 5:34)
2. The word al-Ḥarb is used in the sense of qitāl (fighting/battle), as in the following verses:
And if you, [O Muhammad], gain dominance over them in ḥarb (that is, in qitāl/battle), disperse by [means of] them those behind them that perhaps they will be reminded. (al-Anfāl 8:57)
Every time they kindled the fire of ḥarb (that is, qitāl/battle), Allah extinguished it. (al-Māʾida 5:64)