George Herbert was a priest, and refers back to the dress of the priests under the law of Moses. The poem is deceptively simple, but the bite is there.
Holiness on the head,
Light and perfections on the breast,
Harmonious bells below, raising the dead
To lead them unto life and rest:
Thus are true Aarons drest.
Profaneness in my head,
Defects and darkness in my breast,
A noise of passions ringing me for dead
Unto a place where is no rest:
Poor priest, thus am I drest.
Only another head
I have, another heart and breast,
Another music, making live, not dead,
Without whom I could have no rest:
In him I am well drest.
Christ is my only head,
My alone-only heart and breast,
My only music, striking me ev’n dead,
That to the old man I may rest,
And be in him new-drest.
So, holy in my head,
Perfect and light in my dear breast,
My doctrine tun’d by Christ (who is not dead,
But lives in me while I do rest),
Come people; Aaron’s drest.