In Jerome's Epistola 22 ad Eustochium, the famous one where God tells him that he (Jerome) is not a Christian but a Ciceronian, Jerome writes, after being whipped and then offered lenience if he won't read any more Gentile books:
Ego quī in tantō cōnstrictus articulō, vellem etiam majōra prōmittere, dejerāre coepī, et nōmen ejus obtestāns, dīcere, Domine, sī unquam habuerō codicēs saeculārēs, sī lēgerō, tē negāvī.
Translating very literally, I understand that as:
I, who [being] squeezed in such a moment, would have willingly promised even more, began to swear an oath, and, beseeching His name, to say, "Lord, if I ever have worldly books, if I [ever] read [them], then I have denied you."
My question is: given that habuerō and lēgerō are in future tense, why isn't negāvī in future perfect tense (negāverō)? I thought this was the classic situation where the future perfect is called for. Is this just a kind of acceptable sloppiness with tenses (maybe displaying his newfound anti-Ciceronian Latin) or does the perfect tense here mean something special?
As @Draconis and @Joonas pointed out, habuerō and lēgerō are future perfect, not simple future. That's what I get for skipping the exercises for the chapters on these tenses in Lingua Latina Per Se Illustrata. "They're so simple! I won't have trouble remembering these!"
When reading this passage, I simply assumed from sense that the tenses would be future, future, and future perfect. Then I noticed that negāvī was (past) perfect and was led to ask this question, and never bothered to think about the other two verbs—even when typing them in! This makes me wonder how many other passages I've misread because I assumed the tense from sense and not from the verbs' actual endings.