I heard Ibn Abbas say, "We used to memorize hadith, and hadith was preserved from the Messenger of Allah ﷺ. But once you began to ride both the difficult and the docile mounts, then it is far beyond reach."
حدثنا العباس بن عبد العظيم العنبري حدثنا عبد الرزاق أنبأنا معمر
سمعت ابن عباس يقول إنما كنا نحفظ الحديث والحديث يحفظ عن رسول الله ﷺ فأما إذا ركبتم الصعب والذلول فهيهات
Muslim narrated it in the introduction to his Sahih, in the chapter prohibiting narration from daif narrators, etc., hadith no. 7, from the hadith of Abdul-Razzaq with this chain.