In the poem the narrator, whom we identify with Herbert, rebels against the constraints of his life as a priest, saying his harvest in life is a "thorn" and he would prefer to escape to a foreign land where he could enjoy the world's pleasures. The imagery of imprisonment, such as "ropes" and a "cage"—as well as the collar as not only the clerical collar, but the collar that would chain a dog or a prisoner—contrasts with images of bounty and sensual pleasure, such as corn, wine, and cordial fruit. In contrast to his "thorn," the narrator wishes for flowers and garlands, such as would decorate a celebrated hero.
Herbert became a priest towards the end of his short life. He was a wealthy man, related to the Earl of Pembroke, so he didn't need the income of his priesthood and had been used to the high life at the center of power. The work of a priest must have seemed humble and hard in contrast, as well as low in material rewards. In this poem, Herbert plays on the "carpe diem" theme, which means "seize the day" or enjoy life and love now, as death can come at any time. Herbert, however, turns this theme on its head, finishing his "fierce and wild" raving as he responds to God's call:
"But as I raved and grew more fierce and wild At every word, Methought I heard one calling, Child! And I replied My Lord."
The final lines reduce the former rebellion to a childish status as the narrator reenters his dutiful relationship with God.
The Collar suggests that life is hard when a person must keep to a strict moral and holy code and therefore, in this poem, Herbert uses his rantings as part of a cathartic process, at the end of which he is able to recognize
a patient God who ultimately gives more than he asks.
Once he realizes that it is not necessary to be bound by the “rope of sands” and any moral restrictions, and there will be no more "sighs" and "tears" to frustrate him, he is determined to make the most of "double pleasures." The speaker even attempts to make his own saying, almost like a proverb
“He that forbears/ To suit and serve his need,/ Deserves his load.”
The rebelliousness and almost chaotic structure of the poem comes to a more subtle end. After the rantings of an angry man, restricted almost literally by a "collar" around his neck, the conclusion is hopeful and calm. For all the speaker's uncertainty, God is accepting and protective of all his children.
The "Child" who answers "Lord" is able to come to a realization that service is not a burden and devotion brings its own freedom.