'Abdullah reported that the Prophet, may Allah bless him and grant him peace, said, "You must be truthful. Truthfulness leads to dutifulness and dutifulness leads to the Garden. A man continues to tell the truth until he is written as a siddiq with Allah. Beware of lying. Lying leads to deviance and deviance leads to the Fire. A man continues to lie until he is written as a liar with Allah."  

عَنِ النَّبِيِّ ﷺ قَالَ عَلَيْكُمْ بِالصِّدْقِ فَإِنَّ الصِّدْقَ يَهْدِي إِلَى الْبِرِّ وَإِنَّ الْبِرَّ يَهْدِي إِلَى الْجَنَّةِ وَإِنَّ الرَّجُلَ يَصْدُقُ حَتَّى يُكْتَبَ عِنْدَ اللهِ صِدِّيقًا وَإِيَّاكُمْ وَالْكَذِبَ فَإِنَّ الْكَذِبَ يَهْدِي إِلَى الْفُجُورِ وَالْفُجُورَ يَهْدِي إِلَى النَّارِ وَإِنَّ الرَّجُلَ لَيَكْذِبُ حَتَّى يُكْتَبَ عِنْدَ اللهِ كَذَّابًا  

'Abdullah said, "Lying is not correct, neither in seriousness nor in jest. None of you should promise his child something and then not give it to him."  

عَنْ عَبْدِ اللهِ قَالَ لاَ يَصْلُحُ الْكَذِبُ فِي جِدٍّ وَلاَ هَزْلٍ وَلاَ أَنْ يَعِدَ أَحَدُكُمْ وَلَدَهُ شَيْئًا ثُمَّ لاَ يُنْجِزُ لَهُ