إِنَّ الصِّدْقَ يَهْدِي إِلَى الْبِرِّ، وَإِنَّ الْبِرَّ يَهْدِي إِلَى الْجَنَّةِ، وَإِنَّ الرَّجُلَ لَيَصْدُقُ حَتَّى يَكُونَ صِدِّيقًا، وَإِنَّ الْكَذِبَ يَهْدِي إِلَى الْفُجُورِ، وَإِنَّ الْفُجُورَ يَهْدِي إِلَى النَّارِ، وَإِنَّ الرَّجُلَ لَيَكْذِبُ، حَتَّى يُكْتَبَ عِنْدَ اللَّهِ كَذَّابًا
Truthfulness leads to righteousness, and righteousness leads to Paradise. A man keeps telling the truth until he becomes a truthful one. Lying leads to wickedness, and wickedness leads to the Fire. A man keeps lying until he is written down with Allah as a liar.
آيَةُ الْمُنَافِقِ ثَلاَثٌ إِذَا حَدَّثَ كَذَبَ، وَإِذَا وَعَدَ أَخْلَفَ، وَإِذَا اؤْتُمِنَ خَانَ
The signs of a hypocrite are three: when he speaks, he lies; when he promises, he breaks it; and when he is trusted, he betrays.
دَعْ مَا يَرِيبُكَ إِلَى مَا لاَ يَرِيبُكَ فَإِنَّ الصِّدْقَ طُمَأْنِينَةٌ وَإِنَّ الْكَذِبَ رِيبَةٌ
Leave what makes you doubt for what does not make you doubt. Truthfulness is peace of mind, and lying is doubt.
أَنَا زَعِيمٌ بِبَيْتٍ فِي رَبَضِ الْجَنَّةِ لِمَنْ تَرَكَ الْمِرَاءَ وَإِنْ كَانَ مُحِقًّا وَبِبَيْتٍ فِي وَسَطِ الْجَنَّةِ لِمَنْ تَرَكَ الْكَذِبَ وَإِنْ كَانَ مَازِحًا وَبِبَيْتٍ فِي أَعْلَى الْجَنَّةِ لِمَنْ حَسَّنَ خُلُقَهُ
I guarantee a house on the edge of Paradise for whoever gives up arguing even when he is right, a house in the middle of Paradise for whoever gives up lying even when he is joking, and a house in the highest part of Paradise for whoever makes his character good.
وَيْلٌ لِلَّذِي يُحَدِّثُ فَيَكْذِبُ لِيُضْحِكَ بِهِ الْقَوْمَ وَيْلٌ لَهُ وَيْلٌ لَهُ
Woe to the one who speaks and lies to make people laugh. Woe to him, woe to him.
وَمَا أَرَدْتِ أَنْ تُعْطِيهِ ... أَمَا إِنَّكِ لَوْ لَمْ تُعْطِيهِ شَيْئًا كُتِبَتْ عَلَيْكِ كِذْبَةٌ
(My mother called me and said: Come here, I will give you something. The Prophet ﷺ asked her:) What did you mean to give him? (She said: A date. He said:) If you had not given him anything, a lie would have been written against you.
كَفَى بِالْمَرْءِ إِثْمًا أَنْ يُحَدِّثَ بِكُلِّ مَا سَمِعَ
It is enough of a sin for a person to pass on everything he hears.
Sahih Muslim has the same hadith in its introduction, with the words "enough of a lie".
مَنْ تَعَمَّدَ عَلَىَّ كَذِبًا فَلْيَتَبَوَّأْ مَقْعَدَهُ مِنَ النَّارِ
Whoever deliberately tells a lie about me, let him take his seat in the Fire.
This is why it matters to check a hadith before sharing it. It is one of the most widely narrated hadith of all.
أَلاَ أُنَبِّئُكُمْ بِأَكْبَرِ الْكَبَائِرِ ... الإِشْرَاكُ بِاللَّهِ، وَعُقُوقُ الْوَالِدَيْنِ ... أَلاَ وَقَوْلُ الزُّورِ
Shall I not tell you the greatest of the major sins? ... Associating partners with Allah and disobeying parents ... And beware of false speech. (He was reclining, then sat up and kept repeating it.)
الْبَيِّعَانِ بِالْخِيَارِ مَا لَمْ يَتَفَرَّقَا ـ أَوْ قَالَ حَتَّى يَتَفَرَّقَا ـ فَإِنْ صَدَقَا وَبَيَّنَا بُورِكَ لَهُمَا فِي بَيْعِهِمَا، وَإِنْ كَتَمَا وَكَذَبَا مُحِقَتْ بَرَكَةُ بَيْعِهِمَا
The buyer and the seller may cancel the sale until they part. If they tell the truth and make everything clear, their sale is blessed for them. If they hide things and lie, the blessing of their sale is wiped out.
ثَلاَثَةٌ لاَ يُكَلِّمُهُمُ اللَّهُ يَوْمَ الْقِيَامَةِ وَلاَ يَنْظُرُ إِلَيْهِمْ وَلاَ يُزَكِّيهِمْ وَلَهُمْ عَذَابٌ أَلِيمٌ ... الْمُسْبِلُ وَالْمَنَّانُ وَالْمُنَفِّقُ سِلْعَتَهُ بِالْحَلِفِ الْكَاذِبِ
There are three whom Allah will not speak to on the Day of Resurrection, nor look at, nor purify, and they will have a painful punishment ... the one who lets his lower garment trail, the one who reminds people of what he gave them, and the one who sells his goods with a false oath.
The scholars explain the first as dragging the garment out of pride.
لَيْسَ الْكَذَّابُ الَّذِي يُصْلِحُ بَيْنَ النَّاسِ، فَيَنْمِي خَيْرًا، أَوْ يَقُولُ خَيْرًا
The one who makes peace between people, passing on good or saying good, is not a liar.