ENOfficial
'Umar said, "A man is reckoned to be lying when he gives voice to all that he hears." He said, "As for cases of indirect allusion, are they enough to keep a Muslim from lying?"
Source: sunnah.com
Other translations
Arabic
حَدَّثَنَا الْحَسَنُ بْنُ عُمَرَ، قَالَ: حَدَّثَنَا مُعْتَمِرٌ قَالَ أَبِي: حَدَّثَنَا ابْنُ عُمَرَ، عَنْ عُمَرَ، فِيمَا أَرَى شَكَّ أَبِي، أَنَّهُ قَالَ: حَسْبُ امْرِئٍ مِنَ الْكَذِبِ أَنْ يُحَدِّثَ بِكُلِّ مَا سَمِعَ.
sunnah.com