The beams so revered and strong/why shouldest thou think colloquial arrangement

Thy beams, so reverend and strong

Why shouldst thou think?

I could eclipse and cloud them with a wink,

But that I would not lose her sight so long.

Donne shows his knowledge of recent scientific discovery in talking of the sun's beams. It was a recent idea that humans saw objects because of the light cast on them.

Seeing "beams" followed by "strong" gives a metaphorical sense of wooden beams, making the reference feel less frilly and more solid.

But then Donne reverses our expectations to mock the sun again. It looked like he was saying something nice there but reveals the verb and the rest of the question: "Why would anyone think that?" Once again, Donne withheld this question for the readers response.

That question is like a hypothetical proposition that needs a proof. Donne is ready to prove his case. Why do I dare to insult the sun? Well because I just close my eyes then all those sunbeams disappear. he believes he is above the sun because his eyes can cause eclipses and cloud those sun beams.

he's doing this all for the honor of a lady and bragging about why he's better and that he could rule the sun BUT that would mean closing his eyes and taking them off her. so kinda sweet kinda like every other medieval jock.