A Vivid Picture of the Severity of the Judgment.
“You therefore, son of man, prophesy, and smite your hands together, and let the sword be doubled the third time (or ‘be doubled, yes tripled'), the sword for those to be mortally wounded. It is the sword of the great one for those to be mortally wounded which enters into their chambers. I have set the point of the sword against all their gates that their heart may melt and that their stumblings may be multiplied. Ah, it is made like lightning, it is pointed for slaughter. Make yourself one (or ‘gather yourself'), go to the right, set yourself in array, go to the left, wherever your face is set.”
The slight differences in translation of this complicated Hebrew (complicated to us rather than necessarily to the early readers of Ezekiel) make little difference to the overall sense.
This is a vivid picture of the final slaughter, as the sword sent by Yahweh does its work, and the prophet is to smite his hands to reveal his intensity, because it is bringing about the fulfilling of God's purposes. The picture is intended to amplify the impact of the passage. While God's people grieve, as Ezekiel did (Ezekiel 21:12), at the need for such judgments, they must be filled with fierce joy that God's purposes are being carried into effect.
The sword is to be multiplied because of the intensity of the judgment, the sword that will mortally wound. The ‘great one' may be Yahweh Himself, or it may refer to the Babylonian king or army, but the sword will enter into their very houses in which they will be slain. It is set by God against their gates so that they have no effective defences and will be thrown into panic and disarray. It is invincible, made like lightning and with a sharpened point (compare the sword in Genesis 3:24). There will be no escape.
‘Make yourself one (or ‘gather yourself'), go to the right, set yourself in array, go to the left, wherever your face is set.'
The command may have been to Ezekiel as he portrayed in vivid mime the use of the sword, or it may be a general command to the wielders of the sword. But in either case the thought is that the handler of the sword would prepare himself and slay on all sides, right and left. There would be no avoiding it.