The Spoils of War - 8:7 Allah had promised you to defeat one of the two groups, but you wanted to meet the weaker of the two. But Allah wishes to realize the truth by His words and to cut off the pursuit of the disbelievers.
Why does Allah wish to cut off and destroy the disbelievers?
Prophet Noah/71:26 "Noah said, "My Lord, do not leave a single disbeliever on the earth."
Prophet Noah/71:27 "He said, "If you leave them, they will lead your servants astray and they will give birth only to lowly disbelievers."
Prophet Noah/71:28 My Lord, forgive me and my parents and those who enter my house as believers and the believing men and women, and increase only the destruction of the wrongdoers.

The Spoils of War/8:7 Allah had promised you to defeat one of the two groups, but you wanted to meet the weaker of the two. But Allah wishes to realize the truth by His words and to cut off the pursuit of the disbelievers.