Allah the Exalted has said:
رياض الصالحينAbū Zakariyyā Muḥyī al-Dīn Yaḥyā ibn Sharaf al-Nawawī٤ - باب الصدق
٤ - باب الصدق
O you who have believed, fear Allāh and be with those who are true.
And He the Exalted has said:
إِنَّ ٱلْمُسْلِمِينَ وَٱلْمُسْلِمَـٰتِ وَٱلْمُؤْمِنِينَ وَٱلْمُؤْمِنَـٰتِ وَٱلْقَـٰنِتِينَ وَٱلْقَـٰنِتَـٰتِ وَٱلصَّـٰدِقِينَ وَٱلصَّـٰدِقَـٰتِ وَٱلصَّـٰبِرِينَ وَٱلصَّـٰبِرَٰتِ وَٱلْخَـٰشِعِينَ وَٱلْخَـٰشِعَـٰتِ وَٱلْمُتَصَدِّقِينَ وَٱلْمُتَصَدِّقَـٰتِ وَٱلصَّـٰٓئِمِينَ وَٱلصَّـٰٓئِمَـٰتِ وَٱلْحَـٰفِظِينَ فُرُوجَهُمْ وَٱلْحَـٰفِظَـٰتِ وَٱلذَّٰكِرِينَ ٱللَّهَ كَثِيرًا وَٱلذَّٰكِرَٰتِ أَعَدَّ ٱللَّهُ لَهُم مَّغْفِرَةً وَأَجْرًا عَظِيمًا
Indeed, the Muslim men and Muslim women, the believing men and believing women, the obedient men and obedient women, the truthful men and truthful women, the patient men and patient women, the humble men and humble women, the charitable men and charitable women, the fasting men and fasting women, the men who guard their private parts and the women who do so, and the men who remember Allāh often and the women who do so - for them Allāh has prepared forgiveness and a great reward.
وَقالَ تَعَالَى:
And He the Exalted has said:
طَاعَةٌ وَقَوْلٌ مَّعْرُوفٌ ۚ فَإِذَا عَزَمَ ٱلْأَمْرُ فَلَوْ صَدَقُوا۟ ٱللَّهَ لَكَانَ خَيْرًا لَّهُمْ
Obedience and good words. And when the matter [of fighting] was determined, if they had been true to Allāh, it would have been better for them.
وأما الأحاديث:
As for the hadiths [on this theme]:
فالأول: عن ابن مسعود - ﵁ - عن النَّبيّ - ﷺ - قَالَ: «إنَّ الصِّدقَ يَهْدِي إِلَى البرِّ، وإنَّ البر يَهدِي إِلَى الجَنَّةِ، وإنَّ الرَّجُلَ لَيَصدُقُ حَتَّى يُكْتَبَ عِنْدَ اللهِ صِدِّيقًا. وَإِنَّ الكَذِبَ يَهْدِي إِلَى الفُجُورِ، وَإِنَّ الفُجُورَ يَهدِي إِلَى النَّارِ، وَإِنَّ الرَّجُلَ لَيَكْذِبُ حَتَّى يُكتَبَ عِنْدَ الله كَذَّابًا». مُتَّفَقٌ عَلَيهِ.
The first: From Ibn Masʿūd (may Allah be pleased with him), from the Prophet (peace and blessings be upon him), who said: "Truthfulness leads to righteousness, and righteousness leads to Paradise. A man keeps speaking the truth until he is recorded with Allah as a truthful one (ṣiddīq). And falsehood leads to wickedness, and wickedness leads to the Fire. A man keeps lying until he is recorded with Allah as an utter liar." Agreed upon.
الثاني: عن أبي محمد الحسن بنِ عليِّ بن أبي طالب ﵄، قَالَ: حَفِظْتُ مِنْ رَسُول الله - ﷺ: «دَعْ مَا يَرِيبُكَ إِلَى مَا لاَ يَرِيبُكَ؛ فإنَّ الصِّدْقَ طُمَأنِينَةٌ، وَالكَذِبَ رِيبَةٌ». رواه الترمذي، وَقالَ: «حديث صحيح». قوله: «يَريبُكَ» هُوَ بفتح الياء وضمها: ومعناه اتركْ مَا تَشُكُّ في حِلِّهِ وَاعْدِلْ إِلَى مَا لا تَشُكُّ فِيهِ.
The second: From Abū Muḥammad al-Ḥasan ibn ʿAlī ibn Abī Ṭālib (may Allah be pleased with them both), who said: I memorised from the Messenger of Allah (peace and blessings be upon him): "Leave what makes you doubt for what does not make you doubt; for truthfulness is tranquillity, and falsehood is misgiving." Narrated by al-Tirmidhī, who said: "A sound hadith." His expression "yarībuka" is [read] with a fatḥah on the yāʾ or with a ḍammah on it; its meaning is: abandon whatever you doubt as to its lawfulness, and turn to what you do not doubt.
الثالث: عن أبي سفيانَ صَخرِ بنِ حربٍ - ﵁ - في حديثه الطويلِ في قصةِ هِرَقْلَ ، قَالَ هِرقلُ: فَمَاذَا يَأَمُرُكُمْ - يعني: النَّبيّ - ﷺ - قَالَ أبو سفيانَ: قُلْتُ: يقولُ: «اعْبُدُوا اللهَ وَحدَهُ لا تُشْرِكوُا بِهِ شَيئًا، وَاتْرُكُوا مَا يَقُولُ آبَاؤُكُمْ، ويَأْمُرُنَا بالصَلاةِ، وَالصِّدْقِ، والعَفَافِ، وَالصِّلَةِ» مُتَّفَقٌ عَلَيهِ.
The third: From Abū Sufyān Ṣakhr ibn Ḥarb (may Allah be pleased with him), in his lengthy hadith concerning the story of Heraclius. Heraclius said: "What does he"—meaning the Prophet (peace and blessings be upon him)—"command you?" Abū Sufyān said: I said: He says: "Worship Allah alone and associate nothing with Him; abandon what your forefathers say." And he commands us to prayer, truthfulness, chastity, and the maintaining of family ties. Agreed upon.
الرابع: عن أبي ثابت، وقيل: أبي سعيد، وقيل: أبي الوليد، سهل ابن حُنَيْفٍ وَهُوَ بدريٌّ ﵁: أنَّ النَّبيّ - ﷺ - قَالَ: «مَنْ سَأَلَ اللهَ تَعَالَى الشَّهَادَةَ بِصِدْقٍ بَلَّغَهُ مَنَازِلَ الشُّهَدَاءِ وَإِنْ مَاتَ عَلَى فِرَاشِهِ». رواه مسلم.
The fourth: From Abū Thābit—and it is said, Abū Saʿīd; and it is said, Abū al-Walīd—Sahl ibn Ḥunayf, who was a participant at Badr (may Allah be pleased with him): that the Prophet (peace and blessings be upon him) said: "Whoever asks Allah the Exalted for martyrdom with sincerity, He will raise him to the ranks of the martyrs, even if he dies upon his bed." Narrated by Muslim.
الخامس: عن أبي هريرةَ - ﵁ - قَالَ: قَالَ رَسُولُ الله - ﷺ: «غَزَا نبيٌّ مِنَ الأنْبِياءِ - صَلَوَاتُ اللهِ وَسَلاَمُهُ عَلَيْهمْ - فَقَالَ لِقَومهِ: لا يَتْبَعَنِّي رَجُلٌ مَلَكَ بُضْعَ امْرَأةٍ وَهُوَ يُريدُ أَنْ يَبْنِي بِهَا وَلَمَّا يَبْنِ بِهَا، وَلا أحَدٌ بَنَى بُيُوتًا لَمْ يَرْفَعْ سُقُوفَهَا، وَلا أحَدٌ اشْتَرَى غَنَمًا أَوْ خَلِفَاتٍ وَهُوَ يَنْتَظِرُ أَوْلادَها . فَغَزا فَدَنَا مِنَ القَرْيَةِ صَلاةَ العَصْرِ أَوْ قَريبًا مِنْ ذلِكَ، فَقَالَ لِلشَّمْسِ: إِنَّكِ مَأمُورَةٌ وَأنَا مَأمُورٌ، اللَّهُمَّ احْبِسْهَا عَلَيْنَا، فَحُبِسَتْ حَتَّى فَتَحَ اللهُ عَلَيهِ، فَجَمَعَ الغَنَائِمَ فَجَاءتْ - يعني النَّارَ - لِتَأكُلَهَا فَلَمْ تَطعَمْها، فَقَالَ: إنَّ فِيكُمْ غُلُولًا ، فَلْيُبايعْنِي مِنْ كُلِّ قَبِيلَةٍ رَجُلٌ، فَلَزِقَتْ يَدَ رَجُلٍ بِيَدِهِ فَقَالَ: فِيكُمُ الغُلُولُ فَلتُبَايِعْنِي قَبِيلتَكَ، فَلَزقَت يَدُ رَجُلَين أو ثَلاَثة بيده، فقال: فيكم الغُلُولَ، فَجَاؤُوا بِرَأْس مثلِ رَأسِ بَقَرَةٍ مِنَ الذَّهَبِ، فَوَضَعَهَا فَجَاءَت النَّارُ فَأكَلَتْها. فَلَمْ تَحلَّ الغَنَائِمُ لأحَدٍ قَبْلَنَا، ثُمَّ أحَلَّ الله لَنَا الغَنَائِمَ لَمَّا رَأَى ضَعْفَنا وَعَجْزَنَا فَأحَلَّهَا لَنَا». مُتَّفَقٌ عَلَيهِ. «الخَلِفَاتُ» بفتحِ الخَاءِ المعجمة وكسر اللامِ: جمع خِلفة وهي الناقة الحامِل.
The fifth: From Abū Hurayrah (may Allah be pleased with him), who said: The Messenger of Allah (peace and blessings be upon him) said: "A prophet from among the prophets—Allah's blessings and peace be upon them—went out on a military expedition, and he said to his people: Let no man follow me who has married a woman and wishes to consummate the marriage with her but has not yet done so; nor anyone who has built houses whose roofs he has not yet raised; nor anyone who has bought sheep or pregnant she-camels and is awaiting their offspring. So he set out, and he drew near to the town at the time of the ʿAṣr prayer, or close to it. He said to the sun: You are commanded, and I am commanded. O Allah, hold it back for us. So it was held back until Allah granted him victory. He gathered the spoils, and it came—meaning the fire—to consume them, but it did not consume them. He said: There is misappropriated booty among you; so let one man from each tribe pledge allegiance to me. The hand of a man stuck fast to his hand, and he said: The misappropriated booty is among you, so let your tribe pledge allegiance to me. Then the hands of two or three men stuck fast to his hand, and he said: The misappropriated booty is among you. So they brought a head [of gold] like the head of a cow, of gold, and he placed it down, and the fire came and consumed it. Plunder was not lawful for anyone before us; then Allah made the spoils lawful for us when He saw our weakness and incapacity, so He made them lawful for us." Agreed upon. "Al-khalifāt"—with a fatḥah on the dotted khāʾ and a kasrah on the lām—is the plural of khilfah, which is the pregnant she-camel.
السادس: عن أبي خالد حَكيمِ بنِ حزامٍ - ﵁ - قَالَ: قَالَ رسولُ الله - ﷺ: «البَيِّعَانِ بالخِيَار مَا لَمْ يَتَفَرَّقَا، فَإنْ صَدَقا وَبيَّنَا بُوركَ لَهُمَا في بيعِهمَا، وإنْ كَتَمَا وَكَذَبَا مُحِقَتْ بركَةُ بَيعِهِما». مُتَّفَقٌ عَلَيهِ.
The sixth: From Abū Khālid Ḥakīm ibn Ḥizām (may Allah be pleased with him), who said: The Messenger of Allah (peace and blessings be upon him) said: "The two parties to a sale retain the option [to annul it] so long as they have not parted; so if they are truthful and make [matters] clear, their transaction will be blessed for them; but if they conceal and lie, the blessing of their transaction will be wiped out." Agreed upon.