Is eating obligatory for the non-fasting invitee?

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If the invitee is not fasting, eating is preferable as it is a stronger demonstration of honoring the host and pleasing their heart, thereby better fulfilling the purpose of the invitation. However, eating is not obligatory for the non-fasting person. The opinion of the Shafi'i school suggests that eating becomes obligatory based on the Prophet's statement, 'And if he is not fasting, then let him eat,' and because eating is the primary objective of the invitation. The definitive view is that the obligation lies only in responding to the invitation, as evidenced by the Prophet's statement, 'If one of you is invited, he should respond; if he wishes, he eats, and if he wishes, he leaves,' which is a sound hadith. Furthermore, if eating were obligatory, it would be obligatory for the person observing a voluntary fast, but since it is not obligatory for the one voluntarily fasting, it cannot be obligatory for the one who is not fasting. While the opposing view claims the purpose is eating, the sound argument is that the purpose is the acceptance of the invitation itself, which is why it remains obligatory even for the fasting person who does not eat.