The world is charged with the grandeur of God. (1)
"Charged" is a versatile word – charged with a crime, charged money, charged batteries. It can also imply being responsible for the care of someone or something. You can plug these in and see what happens. Some work better than others, depending on individual views about religion, and the divine. As the poem progresses, we learn that the speaker closely connects the grandeur of God to the natural world for the speaker.
Why do men then now not reck his rod? (4)
This line is often interpreted as "why don’t people heed God’s authority?" It seems to be deeper than that. We know that "reck" also means "care for," and that "rod" is sometimes used to mean "tribe," in the Bible. You can fully explore all the words’ definitions and come up with a very complicated argument. Here’s our interpretation: "Why don’t people take care of that which has God’s force running through it?"
[…] last lights off the black West went Oh, morning! (11-12)
These two lines remind us of the title of a famous work by St. John of the Cross, a Roman Catholic mystic, and a poet. It’s called The Dark Night of the Soul. It’s about the struggle to find light in the darkness of existence.