Ezekiel had warned the people about this event, and it had finally happened (see also 2 Kings 25:1–2).
has laid siege (literally is leaning on): The same words were used when a worshiper placed his hands on the animal he brought for sacrifice (Leviticus 1:4; 3:2).
When the worshiper pressed his hands on the animal, he showed that the animal was taking his place.
In this picture, Jerusalem is like that animal. The city is shown as a sacrificial lamb that will be killed. Its destruction would display God’s glory and justice.