Command to be honest and loyal with non-Muslims
Islam lays great stress on fulfilling promises. The Holy Prophet (Sallallahu alaihi wa sallam) asked Hadhrat Hudhaifa and his father to fulfill the promise they had made to the disbelievers even though that promise was a forced one. There is a Hadith in Sahih Muslim:
حَدَّثَنَا حُذَيْفَةُ بْنُ الْيَمَانِ قَالَ مَا مَنَعَنِى أَنْ أَشْهَدَ بَدْرًا إِلاَّ أَنِّى خَرَجْتُ أَنَا وَأَبِى - حُسَيْلٌ - قَالَ فَأَخَذَنَا كُفَّارُ قُرَيْشٍ قَالُوا إِنَّكُمْ تُرِيدُونَ مُحَمَّدًا فَقُلْنَا مَا نُرِيدُهُ مَا نُرِيدُ إِلاَّ الْمَدِينَةَ. فَأَخَذُوا مِنَّا عَهْدَ اللَّهِ وَمِيثَاقَهُ لَنَنْصَرِفَنَّ إِلَى الْمَدِينَةِ وَلاَ نُقَاتِلُ مَعَهُ فَأَتَيْنَا رَسُولَ اللَّهِ -صلى الله عليه وسلم- فَأَخْبَرْنَاهُ الْخَبَرَ فَقَالَ « انْصَرِفَا نَفِى لَهُمْ بِعَهْدِهِمْ وَنَسْتَعِينُ اللَّهَ عَلَيْهِمْ
Translation: It is narrated on the authority of Hadhrat Hudhaifah bin Yamaan (May Allah be pleased with him), he says: Nothing stopped me from participating in the Battle of Badr except that me and my father Husail started (for Madina). He said: The disbelievers of Quraish caught us and asked: Do you desire to meet Hadhrat Muhammad (Sallallahu alaihi wa sallam)? They said: We don’t desire to meet Him, we only want to go to Madina. They made us promise that we would surely go to Madina and will not fight against them. We came to the Holy Prophet (Sallallahu alaihi wa sallam) and informed Him of this. (At the Battle of Badr, when we expressed our desire to join the army), the Holy Prophet (Sallallahu alaihi wa sallam) told us: Both of you go back. We will fulfill the promise for them and seek Allah’s help against them.
The above incident shows us that when a Muslim makes a promise with a non-Muslim compatriot, then Islam declares fulfillment of that promise to be obligatory, provided there is nothing in that promise which goes against the rules of Islam.
There is a Hadith in this regard in Sunan Abu Dawood:
عَنِ الْحَسَنِ بْنِ عَلِىِّ بْنِ أَبِى رَافِعٍ أَنَّ أَبَا رَافِعٍ أَخْبَرَهُ قَالَ بَعَثَتْنِى قُرَيْشٌ إِلَى رَسُولِ اللَّهِ -صلى الله عليه وسلم- فَلَمَّا رَأَيْتُ رَسُولَ اللَّهِ -صلى الله عليه وسلم- أُلْقِىَ فِى قَلْبِىَ الإِسْلاَمُ فَقُلْتُ يَا رَسُولَ اللَّهِ إِنِّى وَاللَّهِ لاَ أَرْجِعُ إِلَيْهِمْ أَبَدًا فَقَالَ رَسُولُ اللَّهِ -صلى الله عليه وسلم- « إِنِّى لاَ أَخِيسُ بِالْعَهْدِ وَلاَ أَحْبِسُ الْبُرُدَ وَلَكِنِ ارْجِعْ فَإِنْ كَانَ فِى نَفْسِكَ الَّذِى فِى نَفْسِكَ الآنَ فَارْجِعْ
Translation: It is narrated on the authority of Hadhrat Hasan bin ‘Ali bin Abu Rafe’ (May Allah be well pleased with them) that Hadhrat ‘Abu Rafe’ (May Allah be well pleased with him)said: I was made an envoy by the Quraish and sent to the Holy Prophet (Sallallahu alaihi wa sallam). He relates: When I was had the honor of seeing the Holy Prophet (Sallallahu alaihi wa sallam), Islam was poured into my heart. I told the Holy Prophet (Sallallahu alaihi wa sallam): I will never return to the non-Muslims. The Holy Prophet (Sallallahu alaihi wa sallam) said: No. I do not break promises and I will not restrain a messenger from going back. You go back. If you still find in your heart what is present now, you may return.