With desire I have desired (epithumiāi epethumēsa). 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 Joh 3:29; Act 4:17.
Before I suffer (pro tou me pathein). Preposition pro with articular infinitive and accusative of general reference, “before the suffering as to me.” Pathein is second aorist active infinitive of paschō.