Apocalypse Explained #528
528. Verse 13. And I beheld, and I heard one angel flying in the midst of heaven, saying with a great voice, Woe, woe, woe, to them that dwell on the earth, by reason of the other voices of the trumpet of the three angels which are about to sound!- "And I beheld, and I heard one angel flying in the midst of heaven," signifies the Lord enlightening all in the heavens concerning the state of the church at its end; "saying with a great voice," signifies in manifestation; "Woe, woe, woe, to them that dwell on the earth by reason of the other voices of the trumpet of the three angels which are about to sound," signifies grievous lamentation over the changes of the state of the church, on account of the turning away from good and truth, and thence damnation.
Mercy
In regular language, "mercy" means being caring and compassionate toward people in poor states. That's a position we are all in relative to the Lord, all the time. Without Him we would be unable to choose what is good; without Him we would be unable to formulate a reasonable thought. Without Him, in fact, we would instantly cease to exist; we have life only because He constantly gives us life. So we are, quite literally, at His mercy. Fortunately, the Lord is caring and compassionate to a degree we cannot fathom. He is the source of all caring and all compassion, and of love itself. His mercy toward us never lessens, never abates, never ends; His whole purpose is to bring each of us, individually, to heaven. The meaning of "mercy" in the Bible is closely tied to this idea: it represents love in a general sense, and the desire for good that comes from love. It can also represent the desire for good and the ideas that describe it when those thoughts and desires are inspired by love of the Lord.