George Herbert is a metaphysical poet whose poems are built around conceits that compare things in surprising ways and that extend through the whole poem structurally and thematically holding it together. To complicate an already complicated poetry style, to the metaphysical aspect and the conceit, Herbert adds one or more secondary conceits and structurally complicated poetry types. "Discipline" exemplifies each of these complicating factors.
"Discipline" is a type of poem called a lament that, according to Encyclopedia Britannica, is "a nonnarrative poem expressing deep grief or sorrow over a personal loss." Laments often open with apostrophes such as the delayed apostrophic "O God" in the first stanza of "Discipline" (apostrophe: a call or appeal to an absent or nonexistent entity). It is also a type of lament called a compliant that, according to Britannica, is a "poem that laments or protests unrequited love or tells of personal misfortune, misery, or injustice."
Throw away thy rod,
Throw away thy wrath:
O my God,
Take the gentle path.
The overarching conceit compares the wrath of God and the rod of discipline to punishment and war. The complaint is that God seems to be taking a wrathful path with the poet and not a "gentle path." The second conceit extends the war metaphor to love and compares love to archery. An implied metaphor ties to power of love to the impossibility of stones bleeding in repentance.
Complaints have a distinctive feature in that at about midway, the complaint against love or injustice or suffering twists and a greater, more important subject is introduced that the original complaint corresponds to. In "Discipline," this twist in subject is from God's wrath and punishment to the power of God's love. In the conclusion, the greater subject is joined back to the original complaint; the original conceit is reiterated; the conflict between the two (original and second complaints) is brought to a resolution. In "Discipline" the conceit focusing on wrath and war (punishment) is reiterated and the conflict between wrath and love is resolved through the primacy (greater importance) of love.
Throw away thy rod;
Though man frailties hath,
Thou art God:
Throw away thy wrath.
This explanation of the structure of the poem should have already shed light on its meaning but here is a brief, more direct explanation. "Discipline" laments and complains about God's approach to teaching the poet persona (the universal representative of humanity) through the punishment of anger and war-like implements. After expressing his "desire" and source of guidance, "thy book," and after humbly noting his tendency to "fail," he begs for God's mercy from "the throne of grace." He goes on by switching topics and expressing the exquisite power of love while elaborating upon the rod/bent/archery/ war implement conceit. The end result of his complaint is that, in the war conceit, personified love is said to be mightier than wrath, "Who can ’scape his bow?" and that, as all-mighty, God can easily throw away wrath and take up the more powerful implement of love.
Love is swift of foot;Love’s a man of war,And can shoot,And can hit from far.