Is there a hadith that prohibits eating from a vendor's goods without his permission, and what are the implications for me if the statement I attributed to the Prophet, may Allah bless him and grant him peace, was incorrect?

The sanctity of property and rights is established by numerous texts, including the hadith: "It is not permissible for a person to take his brother's property without a just cause, and that is because Allah has forbidden the Muslim's property to the Muslim," and "It is not permissible for a man to take his brother's stick without his good will." Therefore, eating from a seller's food without his permission falls under this prohibition. However, the mentioned wording about the Messenger's prohibition of taking from a seller's merchandise without his permission has not been reported.

Regarding the warning against fabricating lies about the Messenger of Allah, peace and blessings be upon him, it applies specifically to the deliberate act. As for the unintentional, there is no sin upon him, as the majority of scholars have held. The fear of narrating too much out of concern for falling into error or mistake, even if it is not sinful, is what led some Companions, such as Umar, Zubair, and Anas, to reduce their narrations.

So, if you mentioned this wording thinking it was a prophetic hadith, there is no sin upon you. However, if you deliberately mentioned it while knowing it was not a hadith, then it is a deliberate fabrication. Therefore, extreme caution should be exercised when transmitting hadiths, as the Companions were very careful in transmitting hadith from the Prophet, peace and blessings be upon him.