The word Nas/ناس/People does not refer to mankind, nor the non-Muslim minorities living under a Muslim authority, it refers to non-Muslim nations and Jihad [i.e. Strive] in general.
Jihad is prescribed for two reasons:
- Establish God's law on the earth, and to free the people from polytheism.
- Defend the Muslim minorities living under repression from a non-Muslim tyrant -> Qur'an [2:190]
Jihad is not:
- Killing innocents -> Qur'an [6:151]
- Forcing Islam without people's will -> Qur'an [2:256]
- Taking the properties of non-Muslim without right -> https://sunnah.com/abudawud:3052
Jihad is not what the western media paints the terrorist groups with, the terrorist groups are not even relevant to what the Prophet [PBUH] was doing in his life and the wars he participated in.
Jihad did not start with Islam, the first time in human history when Allah prescribed Jihad was ~3000 years ago, the time when Allah saved Israel from Egypt and led them to the Holy Land to fight the Canaanites:
يَـٰقَوْمِ ٱدْخُلُوا۟ ٱلْأَرْضَ ٱلْمُقَدَّسَةَ ٱلَّتِى كَتَبَ ٱللَّهُ
لَكُمْ وَلَا تَرْتَدُّوا۟ عَلَىٰٓ أَدْبَارِكُمْ فَتَنقَلِبُوا۟
O my people, enter the Holy Land [i.e., Palestine] which Allah has assigned to you and do not turn back [from fighting in Allah's cause] and [thus] become losers.
Prophet Moses, king David, his son Solomon, these noble Prophets [and all Israelite messengers] were ordered to strive for Allah's cause:
Indeed, it is from Solomon, and indeed, it is: 'In the name of Allah, the Entirely Merciful, the Especially Merciful,
Be not haughty with me but come to me in submission [as Muslims].'
This is what the Prophet did before declaring the war, to inform the nations of God's message, then fight [not kill] until submitting to God's order.
The rise of Islam and its expansion [فتوحات is the Arabic name of Islamic Conquests] was also mentioned in the Old Testament, Isaiah 54:
1 Sing, O barren, thou that didst not bear; break forth into singing, and cry aloud, thou that didst not travail with child: for more are the children of the desolate than the children of the married wife, saith the LORD.
2 Enlarge the place of thy tent, and let them stretch forth the curtains of thine habitations: spare not, lengthen thy cords, and strengthen thy stakes;
3 For thou shalt break forth on the right hand and on the left; and thy seed shall inherit the Gentiles, and make the desolate cities to be inhabited.
Barren -> The Arabs of Kedar, not receiving a messenger after Ishmael [PBUH]
Desolate Woman -> Hajar, mother of the Ishmaelite Arabs
Married Wife -> Sarah, mother of the Israelites
Tent -> The Kingdom of God [as called in the Gospels], the Islamic Caliphate
Right and Left -> East and West of the Holy Land
Inherit the Gentiles -> Inherit the Covenant of Abraham from the Israelites
Allah prescribed Jihad after the covenant with Abraham [Qur'an 2:124], before the covenant; He sent the divine punishment upon the disbelievers Himself, because the believers were minorities among them and couldn't fight.
The case became different after Allah revealed the Torah, at which He stopped the divine punishment and ordered the believers to fight the disbelievers, this was not something Prophet Muhammad had a choice in, it's an order.
They do not break their covenant with Allah and His Messenger, but Allah will enable their enemies to overpower them and take some of what is in their hands. Unless their leaders rule according to the Book of Allah and seek all good from that which Allah has revealed, Allah will cause them to fight one another.