First Simile of the Poems

In the poem: "A Valediction: Forbidding Mourning", there is talk of either going on a journey or a man about to die. Phrases such as: "Whisper to their souls to go, and the breath goes now" make it seem like it is about death. Phrases such as: "Though I must go, endure not yet. and Like th' other foot, obliquely run" make it seem as just a journey. But here is my proposition, the author is trying to say death is another journey on its own. We leave our body and our souls go on a journey unlike any we have ever taken so far. The simile example in this poem is "Like gold to airy thinnes beat."