The language and tone of this sonnet suggest that the body and the soul are connected in a relationship that can be compared to that of a subtle spiritual entity that is compelled, or even forced to, submit to the whims of a tangible being. Of course this is referring to the relationship between the immortal soul and the mortal body here on earth. The body is caught up with the tangible trappings of the material world and the soul cannot free itself until the body has returned to the earth. For this reason I have chosen the words "yoked to" as the phrase to fill in the blank in "Sonnet 146."
Closely examining the registers within the first quatrain shows how the soul is compelled to act in accordance with the desires of the body, even though the soul is fully cognizant of the futility of the material world. The lines one through four describe a relationship that is of two separate but very connected entities, each possessing its own consciousness:
Poor soul, the centre of my sinful earth,
[Yoked to] these rebel powers that thee array,
Why dost thou pine within and suffer dearth,
Painting thy outward walls so costly gay?
In the very first line there are many different registers that appear (which reappear throughout this sonnet), such as the spiritual register (soul and sinful) and that of soil/decomposing (earth). A metaphor is apparent in this line for the "earth" is "sinful" because it is dirty and this foreshadows death and that the body once dead will return to the earth (further evidenced by the presence of words like "worms", "fading", and "end" that appear later in the sonnet). From this we can gather that the soul is "yoked to" to the body for the duration of the bodys life. Another register that is first highlighted in this quatrain is that of war through the words "rebel" and "array" that are written here. This shows that the body is acting against the subtle will of the soul by aligning its material forces of the material world and the fourth line backs up this assertion, where the register of a building is presented. There gains of the body come at the cost of spiritual being as the word "costly" exhibits. Examining these lines, through close reading, leads to the next quatrain where the same registers appear again, adding credence to the choice of the words "yoked to" to fill in the blank in the second line.
In the lines five through eight the registers of a building, death, and war appear again and strengthen the choice of "yoked to" as the words that fit in line two. The words "fading mansion" refer to the body itself and the fact that no amount of material gains will lead to spiritual well being, because the "lease" is so short. For the earth will regain the body in the cycle of life as the "worms" inherit the remains of the body and turn the vessel to dirt once again. But the soul has no choice but to accept the powerful will of the body because it is "yoked to" to the body until it dies.
The third stanza continues the presence of the aforementioned registers and gives rise to new metaphors that appear. The "soul" will eternally live on past the life of its "servant" and through the death of the body the soul will prosper in unrestricted freedom. The eleventh line brings an interesting metaphor to the forefront with the continuation of the spiritual register (evident in the word "divine") in conflict with register of money ("buy" and "selling"), because money is material and has no effect on the spiritual well-being of the soul. The twelfth line continues this metaphor because the soul will be "fed" (in the register of life) while the body will "be rich no more" (the money register). Thus, in the absence of the shallow materialism of the body, the soul will prosper. This shows how the soul is forced, for the time being, to acquiesce to the desires of the body because it is "yoked to" the desires of the body.
The final two lines punctuate the choice of "yoked to" as the proper words to fill in the blank on line two because they show the soul will prosper after it is no longer compelled to act in accordance with the desires of the body. Line thirteen continues the register of feeding and life in conflict with that of death and points to the cycle of life where the body will return to the earth and the soul will live on. The fourteenth line especially brings the whole sonnet together; for once the body is dead the soul will live on forever without death. This is why the choice of the words "yoked to" is the correct one for the blank spot in line two.