Is the saying attributed to Ash-Shafi‘i: "The scholars are in agreement that Allah does not punish for matters in which there is disagreement" authentic?

This article was not seen in the books of Al-Shafi'i, and the saying "what is differed upon is not denounced" is not entirely correct. Rather, the mujtahid is excused in it if he exerts his utmost effort in seeking the truth, as is the muqallid (follower) of a trustworthy scholar. However, one for whom the truth becomes clear yet he opposes it under the pretext of disagreement, or follows his whims, is not excused, because warnings have been issued regarding matters upon which scholars have differed. Sheikh al-Islam Ibn Taymiyyah holds that an excuse is only valid when there is an inability to remove the cause. And whoever falls short in knowing the truth despite being able to do so is not excused. And whoever commits forbidden acts without ijtihad or a permissible taqlid deserves the warning.