Accordingly, promises have been raised to the level of covenants with regard to the obligation of fulfilling them. In this respect, Imam al-Sadiq (‘a) has quoted the Holy Prophet (S) as saying: مَنْ كَانَ يُؤْمِنُ بِاللهِ وَالْيَوْمِ الآخِرِ فَلْيَفِ إِذَا وَعَدَ.
Whoever truly believes in Allah and the Last Day must keep faith with his promise. [^5] Hisham ibn Salim has reported that he heard Imam al-Sadiq (‘a) saying: عِـدَةُ الْمُؤْمِنِ أَخَـاهُ نَـذْرٌ لاَ كَفَّـارَةَ لَهُ، فَمَـنْ أَخْـلَفَ فَبِخُـلْفِ اللهِ بَدَأَ وَلِمَقْتِـهِ تَعَرَّضَ، وَذَلِكَ قَوْلُهُ: يَا أَيُّهَا الَّذِينَ آمَنُوا لِمَ تَقُولُونَ مَا لَا تَفْعَلُونَ (2) كَبُرَ مَقْتًا عِنْدَ اللَّهِ أَنْ تَقُولُوا مَا لَا تَفْعَلُونَ (3) A faithful believer’s promise to his brother-in-faith is a non-expiable vow.
Hence, whoever breaks his promise has in fact broken his promise with Almighty Allah, exposing himself to His wrath. This is the meaning of Almighty Allah’s saying, “O you who believe! Why do you say that which you do not do? It is most hateful to Allah that you should say that which you do not do. (61:2-3)” [^6] 3. Islam has deemed it obligatory to be honest in speech and in one’s dealings with others.
In this regard, Imam al-Sadiq (‘a) is reported to have said: كُونُوا دُعَاةً لِلنَّاسِ بِالْخَيْرِ بِغَيْرِ ألْسِنَتِكُمْ، لِيَرَوْا مِنْكُمُ الإجْتِهَادَ وَالصِّدْقَ وَالْوَرَعَ. Act as heralds to goodness in the milieus of people by other means besides your tongues (i.e.
speech) so that they can become aware of your diligence, honesty, and piety. [^7] Zayd ibn ‘Ali has reported on the authority of his fathers that the Holy Prophet (S) said: إِنَّ أَقْرَبَكُمْ مِنِّي غَداً وَأَوْجَبَكُمْ عَلَيَّ شَفَاعَةً أَصْدَقُكُمْ لِلْحَدِيثِ وَآدَاكُمْ لِلأَمَانَةِ وَأَحْسَنُكُمْ خُلُقاً وَأَقْرَبُكُمْ مِنَ النَّاسِ.
Verily, the closest of you all to me and the worthiest of winning my intercession tomorrow is the most honest in speech, the most observant of trusts, the most well-mannered, and the closest to people. [^8] 4. Islam has determined a number of reciprocal duties of faithful believers towards each other. Let us now refer to some more traditions dealing with this topic. Mu’alla ibn Khunays has reported that he once asked Imam al-Sadiq (‘a) about the duties of Muslims toward one another.