When a church is falling and loses its desire for good, those within it who desire what is good will grieve. That's the state represented by "mourning" in the Bible. On a personal scale this also happens inside us as we move from lower spiritual states to higher ones. To be "comforted" represents an influx of new ideas which can help us move on to a new spiritual state or – on the wider scale – can help rejuvenate or even replace the church.

Here, then, we see the Lord promising the good people of the Jewish church - the ones grieving over its fallen state and the self-serving ways of its leaders – that they would receive ideas that would let them move on to the new church he was establishing in the world.

385. With sword, signifies by falsity. This is evident from the signification of "sword," as being truth fighting against falsity and destroying it; and in a contrary sense falsity fighting against truth and destroying it (of which above, n. 131, 367).