With desire I have desired (επιθυμια επεθυμησα). A Hebraism common in the LXX. Associative instrumental case of substantive and first aorist active indicative of same like a cognate accusative. Peculiar to Luke is all this verse. See this idiom in John 3:29; Acts 4:17.

Before I suffer (προ του με παθειν). Preposition προ with articular infinitive and accusative of general reference, "before the suffering as to me." Παθειν is second aorist active infinitive of πασχω.