LI

Thus can my love excuse the slow offence Of my dull bearer when from thee I speed: From where thou art why should I haste me thence? Till I return, of posting is no need. O! what excuse will my poor beast then find, When swift extremity can seem but slow? Then should I spur, though mounted on the wind, In winged speed no motion shall I know, Then can no horse with my desire keep pace; Therefore desire, of perfect’st love being made, Shall neigh no dull flesh in his fiery race, But love, for love, thus shall excuse my jade: ‘Since from thee going, he went wilful-slow, Towards thee I’ll run, and give him leave to go.’

Sonnet 51 explores the idea of the speaker's desire for his lover and the limitations of physical distance. The speaker acknowledges that his "dull bearer" - likely a horse - moves slowly when he is traveling away from his lover, but he questions why he should hurry to leave her in the first place. He then muses on what excuse his horse will have when he needs to hurry back to his love, suggesting that his desire for her is so intense that even the swiftest horse cannot keep up. In the final couplet, the speaker resolves to give his horse permission to move at a slow pace when leaving his lover, but he himself will run towards her eagerly upon his return. Overall, the sonnet speaks to the power of love and the lengths to which one may go to be with their beloved, even when faced with physical limitations.