A prophet's duty often extends beyond spoken words, requiring him to physically embody the very message he delivers. Following a prophecy concerning the land of Israel, God commands Ezekiel to perform a dramatic public act of deep mourning. He is told to illustrate the sheer magnitude of an approaching disaster—the destruction of the Temple—through his own physical suffering.
God instructs the prophet to sigh and cry out like someone consumed by immense grief. The pain he must project is both emotional and intensely physical. The primary approach among commentators is that this groan must be so heavy and profound that it mimics the sensation of a person's body physically breaking under the weight of an overwhelming tragedy, causing them to collapse from the sorrow [מצודת דוד, רד״ק, אברבנאל]. This is an especially deep sigh, one that can be felt physically radiating down through the chest and into the lower body [ביאור שטיינזלץ]. To convey this heavy distress, the prophet is told to sigh with complete bitterness of heart [מצודת דוד, ביאור שטיינזלץ].
Crucially, this display of sorrow cannot be done in private; it must be performed openly in full view of the Israelites. The primary approach among commentators is that this public spectacle is specifically designed to capture the attention of the onlookers. Seeing the prophet in such a state of agony will naturally prompt the people to ask him what is causing his severe distress. Once they ask, the stage is set for him to answer and deliver the devastating news from Jerusalem: the impending arrival of the sword of Nebuchadnezzar, the king of Babylon, and the fast-approaching destruction [רד״ק, אברבנאל, מלבי״ם].