Majma al-Zawaid — Hadith 18101

Sayyiduna Abdullah bin Abbas (may Allah be pleased with them both) narrates: This verse was recited in the presence of the Prophet (peace and blessings be upon him): "O people, eat of what is on the earth, lawful and good." Then Sayyiduna Sa'd bin Abi Waqqas (may Allah be pleased with him) stood up and said: "O Messenger of Allah! Pray to Allah Almighty that He make me one whose supplications are answered (mustajab al-da'wat)." The Prophet (peace and blessings be upon him) said to him: "O Sa'd! Keep your food pure, and you will become one whose supplications are answered. By the One in whose Hand is the soul of Muhammad (peace and blessings be upon him), a servant throws a single morsel of the unlawful into his stomach and no deed of his is accepted for forty days; and any servant whose flesh has grown from the unlawful, the Fire (that is, Hell) has more right to him."
Al-Tabarani recorded it in al-Mu'jam al-Saghir, and its chain contains narrators whom I do not know.