If you do not see signs [from God] and marvels, you might not ever start to believe.
Jhn 4:48 Except ye see signs and wonders, ye will not believe.
Interesting and Hidden Aspects:
The two verbs in this sentence have forms which can be interpreted in several different ways.
The verb for "seen" is either the present tense or the imperfect tense, which is usually translated as the past tense: "If you do not see" or "If you have not seen."
The verb for "believe" is either the present tense or the aorist tense (ndicating something starting at a discrete point in time), subjunctive mood, which indicates a possibility of something happening: "you do not believe" or "you might not start to believe."
The two Greek words that might be translated as "not" are both used in this sentence, one after another. Double negatives work in Greek. Using both of them accentuates the denial, making the idea both negative objectively and subjectively. To give the feeling, we use "not, ever" in the alternative to accentuate the denial.
Ἐὰν μὴ "Except" is from ean me, which means "if not." "If" is from ean, which is a conditional particle (derived from ei (if)and an (might)) which makes reference to a time and experience in the future that introduces but does not determine an event. "Not" is from mê (me) is the negative used in prohibitions and expressions of doubt meaning "not" and "no."
καὶ "And" is from kai, which is the conjunction joining phrases and clauses, "and," or "but." After words implying sameness, "as" (the same opinion as you). Used in series, joins positive with negative "Not only...but also." Also used to give emphasis, "even", "also," and "just."
ἴδητε, (2nd pl pres ind act or 2nd pl imperf ind act) "See" is from (eido) which means "to see", "to examine", "to perceive", "to behold", "to know how to do", "to see with the mind's eye," and "to know."
οὐ "Not" is from οὐ ou (with me below), which is the negative adverb for facts and statements, negating both single words and sentences. The other negative adverb, μή applies to will and thought; οὐ denies, μή rejects; οὐ is absolute, μή relative; οὐ objective, μή subjective.
μὴ "Not" is from mê (me) (with ou above), which is the negative used in prohibitions and expressions of doubt meaning "not" and "no." As οὐ (ou) negates fact and statement; μή rejects, οὐ denies; μή is relative, οὐ absolute; μή subjective, οὐ objective.
πιστεύσητε (2nd pl aor subj or 2nd pl fut ind) "You will...believe" is from pisteuô (pisteuo), which means "to trust, put faith in, or rely on a person", "to believe in someone's words", "to comply", "to feel confident in a thing," and "to entrust in a thing."