In one narration the wording is: I was among some Companions, and Sayyiduna Mu'awiyah (may Allah be pleased with him) said: "I ask you by Allah: do you know that the Prophet (peace and blessings be upon him) forbade drinking from silver vessels?" They replied: "Allah knows, yes!" Sayyiduna Mu'awiyah (may Allah be pleased with him) said: "And I too bear witness to that."
Imam Ahmad mentioned this narration within a long hadith, and Imam al-Tabarani recorded part of it. The narrators of Imam Ahmad are the narrators of the Sahih, except Abu Shaykh al-Huna'i, and he is thiqah (trustworthy).
Hadith Referenceمجمع الزوائد ومنبع الفوائد / كتاب الأشربة / 8220