The image of a sunbeam passing through water without damaging it echoes some sublime verses by Dante, Paradiso 2: 35-36. But especially, in Medieval and Renaissance art, that image was used to symbolize Mary's virginal conception of Christ. The 'bigoted' Tasso could be quite blasphemous when he felt like doing so.
A minor detail is the rhyme between "parte" as a verb (meaning "[it] divides") and "parte" as a noun (meaning "part"). A solution often adopted by Tasso, unlike Dante and Ariosto. This may be due, in "part" at least, to the fact that he probably wrote a lot of verses in a hurry, then reworked and polished them up, but modifying a rhyme was more difficult than changing a word or two inside a verse.