In Three Men In A Boat (To Say Nothing Of The Dog), the author states in Chapter 10 that at times, there is no language for pain, 'only a moan.' He tells the reader that daytime is often filled with 'fret and care, and our hearts... so full of evil and of bitter thoughts, and the world...so hard and wrong to us.' He goes on to describe the soothing night 'like some great loving mother, gently lays her hand upon our fevered head, and turns our little tear-stained faces up to hers, and smiles; and, though she does not speak, we know what she would say, and lay our hot flushed cheek against her bosom, and the pain is gone.'
However, there are some pains that are so deep that it can only be uttered through moans. It is only then that night, that great comforter, brings one into a 'mightier Presence than her own, and in the wondrous light of that great Presence, all human life lies like a book before us, and we know that Pain and Sorrow are but the angels of God.'
You can see that the author used the language of his time; this novel was published in 1889 by English author Jerome K Jerome. The sentences may be longer and more unwieldy than modern readers are used to, but all the author is really saying here is that sometimes the pain is so deep that even night time brings no comfort, and no words can fully express the depth of that pain. This type of pain can only be eased by what the author says is a greater Presence.
Thanks for the question.