Receiving a divine message is sometimes pictured as the physical act of eating. This striking image represents how a prophecy is completely absorbed deep into the prophet's soul. However, opening the mouth to eat a scroll is not a literal, physical event. Instead, it is a metaphor for a state of profound humility. The prophet makes his soul willing and receptive, and God gives him the wisdom found in the message [רד״ק].
This interaction highlights human dependence on divine help. The prophet must take the first step by willingly opening his mouth, but he is unable to reach such a high spiritual level on his own. He can only achieve this connection through the direct help of God [מלבי״ם]. Therefore, the act of being fed by God means that He is personally placing the words into the prophet's mouth, actively teaching him the message he is meant to share [מצודת דוד].