“Dig through the wall in their sight, and carry your things out through there. In their sight you will bear it on your shoulder, and carry it out in the dark. You will cover your face so that you do not see the ground, for I have set you as a sign to the house of Israel.”
These further instructions would add to the significance of his acts. He was to leave his house through the wall, symbolising surreptitious escape from the city, and he was to leave as it was becoming dark in order to indicate the idea of secrecy and haste. And he was to cover his face so that he could not see the ground.
The houses in Babylonia would be made of sun-dried brick which, with some effort, would not be difficult to hack through, removing the bricks in order to make a way through. The covering of the face was probably to indicate that he was not expecting to see his homeland again so that he could not bear to look at the ground as he left (see Ezekiel 12:11), and it may possibly have also been intended to indicate secrecy and disguise.
And these things were to be ‘a sign', a guarantee of their happening. They would warn the house of Israel, of what was coming. As they watched his actions he was to hope that they would accept that this was really what was going to happen to their fellow-Israelites in Jerusalem. At least when Jerusalem did fall, and it is difficult for us to imagine just how huge a blow that would be to them when it happened, they would recognise that God had been telling them that this was what He was going to do all the time.