Ibn Uyaynah (may Allah have mercy on him) reported with a chain that the Messenger of Allah (ﷺ) said: "People should not cling to my words, for I declare lawful only that which Allah has made lawful for them, and I declare unlawful only that which Allah has made unlawful for them."
Hadith Referenceمسند الإمام الشافعي / كتاب فضائل قريش وغيرهم وأبواب متفرقة / 1797
Hadith Takhrijاسناده ضعيف لاعضاله : اخرجه البيهقي: 76/7 - وفى المعرفة السنن والآثار له 70/7 وعبد الرزاق (8766)۔