Allah says to His Prophet,

وَإِمَّا تَخَافَنَّ مِن قَوْمٍ ...

If you fear from any people,

with whom you have a treaty of peace,

... خِيَانَةً ...

treachery,

and betrayal of peace treaties and agreements that you have conducted with them,

... فَانبِذْ إِلَيْهِمْ ...

then throw back (their covenant) to them,

meaning their treaty of peace.

... عَلَى سَوَاء ...

on equal terms,

informing them that you are severing the treaty. This way, you will be on equal terms, in that, you and they will be aware that a state of war exists between you and that the bilateral peace treaty is null and void,

... إِنَّ اللّهَ لاَ يُحِبُّ الخَائِنِينَ ﴿٥٨﴾

Certainly Allah likes not the treacherous.

This even includes treachery against the disbelievers.

Imam Ahmad recorded that Salim bin `Amir said,

"Mu`awiyah was leading an army in Roman lands, at a time the bilateral peace treaty was valid. He wanted to go closer to their forces so that when the treaty of peace ended, he could invade them. An old man riding on his animal said, `Allahu Akbar (Allah is the Great), Allahu Akbar! Be honest and stay away from betrayal.' The Messenger of Allah said,

وَمَنْ كَانَ بَيْنَهُ وَبَيْنَ قَوْمٍ عَهْدٌ فَلَا يَحُلَّنَّ عُقْدَةً وَلَا يَشُدَّهَا حَتَّى يَنْقَضِي أَمَدُهَا، أَوْ يَنْبُذَ إِلَيْهِمْ عَلَى سَوَاء

Whoever has a treaty of peace with a people, then he should not untie any part of it or tie it harder until the treaty reaches its appointed term. Or, he should declare the treaty null and void so that they are both on equal terms.

When Mu`awiyah was informed of the Prophet's statement, he retreated.

They found that man to be Amr bin Anbasah, may Allah be pleased with him.''

This Hadith was also collected by Abu Dawud At-Tayalisi, Abu Dawud, At-Tirmidhi, An-Nasa'i and Ibn Hibban in his Sahih. At-Tirmidhi said, "Hasan Sahih.''