Surah An-Nisa' (The Women), Verse 90

اِلَّا الَّذِیْنَ یَصِلُوْنَ اِلٰی قَوْمٍ بَیْنَكُمْ وَبَیْنَهُمْ مِّیْثَاقٌ اَوْ جَآءُوْكُمْ حَصِرَتْ صُدُوْرُهُمْ اَنْ یُّقَاتِلُوْكُمْ اَوْ یُقَاتِلُوْا قَوْمَهُمْ وَلَوْ شَآءَ اللّٰهُ لَسَلَّطَهُمْ عَلَیْكُمْ فَلَقٰتَلُوْكُمْ فَاِنِ اعْتَزَلُوْكُمْ فَلَمْ یُقَاتِلُوْكُمْ وَاَلْقَوْا اِلَیْكُمُ السَّلَمَ فَمَا جَعَلَ اللّٰهُ لَكُمْ عَلَیْهِمْ سَبِیْلًا ۟

Illal lazeena yasiloona ilaa qawmim bainakum wa bainahum meesaaqun aw jaaa'ookum hasirat sudooruhum ai yuqaatilookum aw yuqaatiloo qawmahum, wa law shaaa'al laahu lasallatahum 'alaikum falaqaatalookum; fa ini' tazalookum falam yuqaatilookum wa alqaw ilaikumus salama famaa ja'alal laahu lakum 'alaihim sabeelaa

“Except those who join a group between whom and you there is a treaty (of peace), or those who approach you with hearts restraining them from fighting you as well as fighting their own people. If Allah had pleased, He could have given them power over you, and they would have fought you: Therefore if they withdraw from you but fight you not, and (instead) send you (Guarantees of) peace, then Allah Hath opened no way for you (to war against them).”

Quran 4:90 (Yusuf Ali Translation)