Arcana Coelestia # 2528
2528. 'God said to him in the dream' means a perception that was less obscure. This is clear from what has been stated and explained above in 2514. The reason why in this chapter the name 'God' is used but not 'Jehovah', except in the last verse, is that spiritual matters, that is, matters of doctrine concerning faith, are the subject. For when spiritual matters are referred to, the name 'God' is used, but when celestial matters, that is, love and charity, are dealt with, the name Jehovah' is used, see 709, 732, 2001.
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.