Not graded
Sunan ad-Darimi 619
أَخْبَرَنَا مُحَمَّدُ بْنُ الْمُبَارَكِ حَدَّثَنَا الْوَلِيدُ عَنْ الْأَوْزَاعِيِّ عَنْ الزُّهْرِيِّ قَالَ آفَةُ الْعِلْمِ النِّسْيَانُ وَتَرْكُ الْمُذَاكَرَةِ
This hadith has no English translation yet: the Arabic text, the reference and the grade are shown here.
Reported by Ad-Darimi (No. 619).