In this sonnet, the speaker compares the woman who is the subject to the poem to a silken tent. The theme or message the speaker wishes to convey through this metaphor is that the woman is, like a tent, tied to earth in a strong, but supple way that offers him a pleasurable security.
In the woman's case, rather than tied with ropes, she is bound to the earth by "countless silken ties of love and thought." This is a form of "bondage," but as with a tent, it is one of which the woman is hardly aware: her ties are not rigid but let air and breezes in.
The speaker's imagery conveys the beauty and groundedness of the woman. Her "soul," like the central beam of the tent, is "sure" and pointed toward the heavens. Like the tent, she "gently sways" amid ties that are loose, if solid. She is only aware of them, when like the tent in the breeze, a rope grows "taut" and tugs at her. In her case, we can imagine it to be the demand of a loved one pulling at her.
The speaker idealizes the woman he loves, using such lovely imagery as "silken" and "gently sways" to describe her. She provides shelter and security to him in a way that does not restrict, and yet he can rely on her to stay grounded and strong. It should be noted that we see her through his eyes and not as she might describe herself or her situation.
In "The Silken Tent," Frost uses an extended metaphor to illustrate the theme of the multifaceted nature of womanhood. In the metaphor in question, the speaker likens his lover to a tent, with all its paradoxical qualities. Though soft and gentle, the lover, like the tent, also forms a strong, protective barrier against the harshness of nature. And just as the ropes of the tent—loosened by the breeze—sway gently and easily, so too does the woman go freely wherever she likes, freed from her domestic duties.
The woman's strength—and indeed the strength of women in general—is reinforced by the imagery of the supporting tent-pole, which is strong and reliable, just like a woman's soul. Free-spirited though she undoubtedly is, the speaker's lover is still bound by ties of love, however loose those ties may be. In the extended metaphor of the tent, Frost tries to capture the nature of women in all its many facets, in all its richness and complexity.