Tafsir of Ash-Shu`ara' 26:225

See you not that they speak about every subject in their poetry! Ali bin Abi Talhah reported from Ibn Abbas that this means: "They indulge in every kind of nonsense.'' Ad-Dahhak reported that Ibn Abbas said, "They engage in every kind of verbal art.'' This was also the view of Mujahid and others

وأنهم يقولون ما ﻻأ يفعلون