Armida plays on the double meaning of such words as "fé" ("fede" in current Italian) that can refer either to trusting a man or having faith in God, and "preghi" ("preghiere") indicating either pleas or prayers. On the other hand, the link between anthropological trust and religious faith had been clearly stated by St. Augustine.
The phrase "preghi honesti," honest plea, echoes Dante, see e.g. Inferno 2: 113 ("parlare onesto") and Purgatorio 23: 88 ("prieghi devoti"). And especially, Tasso takes from Dante the daring move of calling the Christian God "Jove," see Purgatorio 6: 118, even directly referring to Jesus Christ with the shocking words "crucified Jove." Dante's and Tasso's beloved poet Virgil would faint at that.