וְאֶל־מְצ֤וֹר יְרוּשָׁלִַ֙ם֙ תָּכִ֣ין פָּנֶ֔יךָ וּֽזְרֹעֲךָ֖ חֲשׂוּפָ֑ה וְנִבֵּאתָ֖ עָלֶֽיהָ׃
Und du sollst dein Gesicht auf die Belagerung Jerusalems richten, wobei dein Arm freigelegt ist; und du sollst dagegen weissagen.
Rashi on Ezekiel
And to the siege of Jerusalem which is engraved on the brick, you shall direct your face; when you lie on your left side, the brick should be opposite you, and so too when you lie on your right.
Rashi on Ezekiel
and your arm shall be bared toward them (Other editions read: opposite it), like a fighting man. This symbolizes Nebuchadnezzar, who will fight against it.