Al-Matalib al-'Aliyah 1662 — Accepting the invitation to a wedding

Iyad bin Abi Ashras relates: I saw Sayyiduna Ya'la bin Murrah (may Allah be pleased with him) and invited him to a meal. He came and sat in the gathering while fasting; the people were eating while he (because of the fast) was not eating anything. We said to him: By Allah, had we known that you were fasting, we would never have troubled you! He said: Do not say that, for I heard the Messenger of Allah (peace and blessings be upon him) say: "Accept your brother's invitation, for through it you are in a state of good either way: either it is something right (or a gathering of good) that you are witnessing, or it is something else (an improper situation), in which case you will stop him from it and enjoin him to good."
The imam of the hadith scholars mentions that the mursal report of Imam Mujahid is also narrated in al-Shama'il.