Jami` at-Tirmidhi 1971
Abdullah bin Mas'ud narrated that the Messenger of Allah said:
"Abide by truthfulness. For indeed truthfulness leads to righteousness. And indeed righteousness leads to Paradise. A man continues telling the truth and trying hard to tell the truth until he is recorded with Allah as a truthful person. Refrain from falsehood. For indeed falsehood leads to wickedness, and wickedness leads to the Fire. A slave (of Allah) continues lying and trying hard to lie, until he is recorded with Allah as a liar."
حَدَّثَنَا هَنَّادٌ، حَدَّثَنَا أَبُو مُعَاوِيَةَ، عَنِ الأَعْمَشِ، عَنْ شَقِيقِ بْنِ سَلَمَةَ، عَنْ عَبْدِ اللَّهِ بْنِ مَسْعُودٍ، قَالَ قَالَ رَسُولُ اللَّهِ صلى الله عليه وسلم ‏
"‏ عَلَيْكُمْ بِالصِّدْقِ فَإِنَّ الصِّدْقَ يَهْدِي إِلَى الْبِرِّ وَإِنَّ الْبِرَّ يَهْدِي إِلَى الْجَنَّةِ وَمَا يَزَالُ الرَّجُلُ يَصْدُقُ وَيَتَحَرَّى الصِّدْقَ حَتَّى يُكْتَبَ عِنْدَ اللَّهِ صِدِّيقًا وَإِيَّاكُمْ وَالْكَذِبَ فَإِنَّ الْكَذِبَ يَهْدِي إِلَى الْفُجُورِ وَإِنَّ الْفُجُورَ يَهْدِي إِلَى النَّارِ وَمَا يَزَالُ الْعَبْدُ يَكْذِبُ وَيَتَحَرَّى الْكَذِبَ حَتَّى يُكْتَبَ عِنْدَ اللَّهِ كَذَّابًا ‏"‏ ‏.‏ وَفِي الْبَابِ عَنْ أَبِي بَكْرٍ الصِّدِّيقِ وَعُمَرَ وَعَبْدِ اللَّهِ بْنِ الشِّخِّيرِ وَابْنِ عُمَرَ ‏.‏ قَالَ أَبُو عِيسَى هَذَا حَدِيثٌ حَسَنٌ صَحِيحٌ ‏.‏