Sulaym ibn Amir reported: There was a peace treaty between Mu’awiyah and the Romans. He was marching towards their country, and when the treaty ended, he would surprise attack them. A man came on a horse, saying, “Allah is the Greatest! Let there be faithfulness and not treachery!” They found that he was ‘Amr ibn ‘Abasah. Mu’awiyah sent for him and questioned him about that. ‘Amr said: I heard the Messenger of Allah, peace and blessings be upon him, say, “If one has a covenant with people, he must not strengthen or loosen it until its term comes to an end, or he brings it to an end in agreement with them.” Thus, Mu’awiyah returned with the people.
Source: Sunan al-Tirmidhī 1580
Grade: Sahih (authentic) according to Al-Albani
عن سُلَيْم بْن عَامِرٍ قال كَانَ بَيْنَ مُعَاوِيَةَ وَبَيْنَ أَهْلِ الرُّومِ عَهْدٌ وَكَانَ يَسِيرُ فِي بِلَادِهِمْ حَتَّى إِذَا انْقَضَى الْعَهْدُ أَغَارَ عَلَيْهِمْ فَإِذَا رَجُلٌ عَلَى دَابَّةٍ أَوْ عَلَى فَرَسٍ وَهُوَ يَقُولُ اللَّهُ أَكْبَرُ وَفَاءٌ لَا غَدْرٌ وَإِذَا هُوَ عَمْرُو بْنُ عَبَسَةَ فَسَأَلَهُ مُعَاوِيَةُ عَنْ ذَلِكَ فَقَالَ سَمِعْتُ رَسُولَ اللَّهِ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ يَقُولُ مَنْ كَانَ بَيْنَهُ وَبَيْنَ قَوْمٍ عَهْدٌ فَلَا يَحُلَّنَّ عَهْدًا وَلَا يَشُدَّنَّهُ حَتَّى يَمْضِيَ أَمَدُهُ أَوْ يَنْبِذَ إِلَيْهِمْ عَلَى سَوَاءٍ قَالَ فَرَجَعَ مُعَاوِيَةُ بِالنَّاسِ
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