What's he saying?
"Being your slave what should I do but tend / Upon the hours, and times of your desire?"
Since I'm your slave, all I have to do is whatever you want me to do.
"I have no precious time at all to spend; / Nor services to do, till you require."
How I spend my time and what I do is determined by you.
"Nor dare I chide the world without end hour, / Whilst I, my sovereign, watch the clock for you,"
And I don't complain as I wait for you to need me,
"Nor think the bitterness of absence sour, / When you have bid your servant once adieu;"
And I don't mind when you leave me;
"Nor dare I question with my jealous thought / Where you may be, or your affairs suppose,"
I don't ask you questions about where you are or what you're doing,
"But, like a sad slave, stay and think of nought / Save, where you are, how happy you make those."
But the only thing I think about is where you are and how happy you are making those you're with.
"So true a fool is love, that in your will, / Though you do anything, he thinks no ill."
Love has made me so foolish that I believe you can do no wrong.
Why is he saying it?
Sonnet 57, along with the following sonnet, reveal the fair lord to be abusive of the poet's undying devotion. In addressing this cruelty here, the speaker obviously recognizes it and is commenting upon it. It is as if he is answering a question posed by the fair lord along the lines of, "Why are you so demanding of my time?" However, in the final couplet of Sonnet 58, he resigns himself to the fate of a slave, waiting around for word from the fair lord: "I am to wait, though waiting so be hell, / Not blame your pleasure be it ill or well."
The idea of someone in love being enslaved by the beloved was common. For example, in Sir Philip Sidney's Sonnet 47 from Astrophil and Stella, the speaker asks, "What, have I thus betrayed my liberty? / Can those black beams such burning marks engrave / In my free side? or am I born a slave, / Whose neck becomes such yoke of tyranny?" The "black beams" are Stella's eyes. This theme reappears in Shakespeare's sonnets to the dark lady, as well.
The theme of Sonnets 57 and 58 is reminiscent of the idea presented in Sonnet 26, which declares, "Lord of my love, to whom in vassalage / Thy merit hath my duty strongly knit." However, in Sonnet 26 the devotion is called "duty so great," and the positive attitude of the poet is reflected in words like "merit," "good," "star," "graciously," "fair," "worthy," and "sweet." However, in Sonnet 57 the attitude of the speaker has changed drastically, and his position is one of desperation and resentment. This is reflected in the diction choices of "slave," "services," "bitterness," "sour," "jealous," "sad," "fool," and "ill."
The suffering of the speaker is not just in that he misses the fair lord, but in that he must pretend not to. He pretends this both to the fair lord, whom he is addressing in this and the following sonnet, as well as to himself while he waits. Lines 9-12 make this struggle obvious, since they contradict each other: "Nor dare I question with my jealous thought / Where you may be, or your affairs suppose, / But, like a sad slave, stay and think of nought / Save, where you are, how happy you make those." He claims not to question the fair lord's whereabouts and actions, but he can "think of nought" else.
While the speaker pines away, waiting for the fair lord to show him some attention, it is implied that the fair lord is off being promiscuous somewhere else. Line 2 refers to the times when the fair lord is away from the poet as "times of your desire." Lines 9-10 seem a bit sarcastic: "Nor dare I question with my jealous thought / Where you may be, or your affairs suppose;" the speaker feels "jealous" for a reason, and the idea that the "affairs" of the fair lord are of questionable moral quality is furthered. In the final line of the sonnet, it is clear that whatever the fair lord is up to is distasteful to the poet: "Though you do anything, he thinks no ill."