The speaker’s reference to his “one talent” suggests a third metaphorical meaning of light. Light is a classic motif for knowledge—intellectual illumination. For the writer, light represents inspiration. When the speaker claims that his “light is spent,” one can say that he is lamenting a case of “writer’s block.”

Patience reminds the speaker that God is like a king and has many servants across the world to do his bidding. Some ride over land and ocean carrying out His will, but others simply need to serve him by waiting. Patience relieves the speaker’s anxiety by telling him that it is acceptable to wait for divine inspiration to tell him what God wants him to do.

“Mild yoke” is an allusion to the Bible: “My yoke is easy, my burden is light” (Matthew 11:30). In the law of the Old Testament, Jewish people were required to follow over 600 strict religious laws. Jesus used this metaphor to relieve them of the burden of these laws. He claimed that there were only two laws man needed to follow: love God, love each other. Thus the “yoke” and “burden” of Jesus was both forgiving and “light.” To “bear his mild yoke” means to follow Jesus’s two commandments to love God and love each other.

A “yoke” is a heavy wooden bar attached to the heads of two oxen, horses, or mules so that they can pull a cart or plow. It is designed to limit the animals’ mobility so that they walk together in the direction in which the farmer wants them to go. A yoke is extremely heavy and implies a great burden or difficult task.

This line draws from the Calvinist belief in predestination. Unlike Catholic doctrine, which claimed one could repent in order to save their soul, Calvinists believed that works on earth had no bearing on one’s salvation. People were predestined for either damnation or salvation at the time of their birth. God therefore did not need “man’s works” because only belief revealed one’s internal piety.

Notice that Patience begins speaking at the volta, or thematic turn. This turn marks a change in the speaker’s mentality. He stops despairing about his lost sight and begins to believe that there is divine purpose in what seems like an unfortunate event.

Notice that the rest of the poem is spoken by “Patience.” Patience is a personified entity that embodies “patience,” the capacity to calmly endure pain, affliction, and inconvenience. The personification of human characteristics is a form of allegory that marks this character as the person who will reveal the moral of the poem.

“Fondly” in this time meant foolishly. The speaker immediately apologizes for the question that he has posed by calling himself foolish. In a way, this shows the speaker recant his question.

“Light denied” in this context means blindness. Notice that there is an undercurrent of blame in this metaphor. “Denied” suggests that someone took his sight. This reveals both the speaker’s anger over losing his sight and his inability to express this anger at God.

The first six lines of the poem lead up to this question: “Does God demand that you work if you have lost your sight?” The first six lines of the poem can be seen as the speaker’s extreme uncertainty over whether or not to ask this question. Questioning God’s will was a form of blasphemy that demonstrated one’s lack of faith. Though this speaker does not directly question God’s decision to take away his sight, he does reveal his frustration when he questions what he can do now that he has lost it.

“He” in this context refers to God. The speaker offers the question in the following line with this caveat that if he is chided for his question, he will recant the question. This reveals the speaker’s anxious and apologetic tone.

Milton adopts a Petrarchan rhyme scheme in order to write this sonnet. The first two quatrains follow an ABBA rhyming pattern, and the sestet uses two tercets of CDE. Following the traditional form of a sonnet, the octet presents a problem that the sestet then resolves.

Notice that enjambment, the continuation of a sentence beyond the end of a line, disrupts the meaning of this sentence as a whole. In this part of the sentence, the speaker means that he is bent in service of God, like a servant who is bowing. However, because this line ends with “bent” it seems at first that his soul is “bent” or crooked, meaning it is in some way immoral or wicked. The division of this sentence, and the divergent meanings implicit within this division, demonstrates the underlying uncertainty throughout this poem. The speaker wonders if he will be able to serve God if he cannot exercise his talents and what will become of his soul if he cannot serve God.

This is the only line in the poem that breaks iambic pentameter. “Lodg’d” is stressed instead of “with,” forming a trochee. This deviation from the poem’s meter underscores the meaning of the line. His “one talent,” writing, becomes “useless” when it resides in him.

In line 6, the speaker suggests that his “one talent’ is to present “my true account.” This signals to the reader that the speaker’s talent is writing, an activity that would have been nearly impossible to do in Early Modern England without sight. Because Milton himself went blind in 1652, this poem is conventionally read as autobiographical.

“Ere” is an adverb that means “before.” The speaker expresses disbelief that he has lost his sight before even half of his life has yet to be lived.

“Spent” can either mean “passed,” as in, "when I consider how I have spent my days," or it can mean “gone,” as in, "when I consider that my sight is gone."

In this context, “light” is a metaphor for both the speaker’s life span and his sight. Since this poem is called “On His Blindness” and we know that Milton went blind in 1652, “light” can be read throughout the poem as a conceit for sight.

Milton's sonnet concerns the universal desire to discover and develop one's talents. The poem suggests that each of us is given one or several gifts which we are obliged to identify, utilize, and develop throughout our lives or else experience disappointment, failure and frustration. The Bhagavad-Gita says something similar and invokes Milton's idea of a "maker" to be served:

In the beginning
The Lord of beings
Created all men,
To each his duty.
'Do this,' He said,
'And you shall prosper.'

The problem for many of us is to discover our talent—or talents. This process may involve a lot of trial and error. But it is obviously a matter of the utmost importance. Milton was neither the first nor last person to consider the great importance of putting one's gifts to work. Many thinkers of the past have their their attentions to this topic:

Blessed is he who has found his work; let him ask no other blessedness.

—Thomas Carlyle (1798–1881)

A man is relieved and gay when he has put his heart into his work and done his best; but what he has said or done otherwise, shall give him no peace. It is a deliverance which does not deliver. In the attempt his genius deserts him; no muse befriends; no invention, no hope.

—Ralph Waldo Emerson (1802–1883)

Note that the speaker's response to his personal loss is a stance of yielding. The word "murmur"—which describes how "Patience" communicates to the speaker—is appropriate to the overall tone of the sonnet. He is resigned to accept whichever fate God imposes upon him. This is also indicated two lines later in the words "mild yoke." When Milton concludes with the words, "They also serve who only stand and wait," he seems to be suggesting that he can serve God by serving as an example of patience, faith, and humility.

In this line, Milton's speaker asks the question, not God. The long and complex sentence beginning with "When I consider how my light is spent" leads the poet to fondly, or foolishly, ask: "Doth God exact day-labour, light denied?" After this question, the first sentence of the sonnet ends with a full stop. All the rest of the sonnet is supposedly spoken by an invisible spirit or angel he calls "Patience." Milton's conclusion suggests that he has made appropriate use of his "one talent" and that God will not scold or "chide" him for wasting it.

This is one of the few lines in the sonnet in which Milton breaks from perfect iambic meter. The first four words are intended to be read with stress on "Lodg'd" and then on "use" in "useless." This emphasis is appropriate since the words are intended to sound like a cry of anguish in an otherwise uniformly tranquil and metrically regular poem betokening Milton's "Patience" and his conviction, as expressed in the beautiful concluding line, that "They also serve who only stand and wait."