The speaker seems to be giving a quiet blessing, or a kind of permission, to someone who has died. "Let him continue in the ground" sounds less like grief than acceptance: the dead man isn't being mourned loudly, just allowed to go on being where he is. The ground is a place "where all things hurry," a striking phrase that makes death feel like a destination everything is already rushing toward. The "strange company who seem to speak" suggests the dead, or perhaps the buried things around him, with the speaker unsure whether they really say anything.
The poem then turns to the living world and lets it go too. Clerks and pursers keep their accounts, and the parson rests. Everyday business and religious authority both feel set aside. The closing image, "the great night come to sit with night," is calm and a little eerie. The mood is hushed and detached, close to peaceful, as if the speaker is easing the dead man, and perhaps himself, into stillness.