According to the Artscroll commentary, the poem claims that the lulav and esrog are held up as a sign of our victory over Satan. If it were actually in the poem, this would be astounding as it seems like a clear reference to the cross, what it symbolizes, and how its used. But as I say, I don’t think the text supports this reading. So it wasn’t the mideival Jewish poet who l tried to connect his lulav and esrog to the artifacts of the surrounding culture. It was Artscroll — which is astounding enough, I suppose.
[Edited later on the same day it was posted, to change my description of DovBear, following comments below.]