Jhn 5:31 If I bear witness of myself, my witness is not true.
If I might give a good report concerning myself, my evidence is not honest.
Interesting and Hidden Aspects:
The verb translated as "bear witness" can seen as either the present tense (as in the KJV) or the subjunctive mood (as in alternative). Given the context, the subjunctive, indicating that something might be done, fits better. Its primary meaning is "to bear witness," but it carries a positive or supportive element that is lost in the English translation.
"Of myself" is more precisely translated as "concerning myself". In the previous verse, the phrase "of my own self" translated a different Greek word as "of" (apo, meaning "from out of") but the same Greek word (emautou) as "my own self" but it is translated more simply as "myself" here.
The word translated as "true" primarily means "unconcealed", a concept we have discussed previously regarding the word for "truth" in Greek, for example in Jhn 14:17, at some length.
Ἐὰν "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.
μαρτυρῶ (1st sg pres subj act or 1st sg pres ind act) "Bear witness" is from martyreo, which means "to bear witness", "to give evidence", "give a good report", "testify to," and "acknowledge the value of." It is the basis for our word "martyr."
οὐκ "Not" is from οὐ ou which is the negative adverb for facts and statements, negating both single words and sentences. The other negative adverb, class="greek">μήapplies to will and thought; class="greek">οὐ denies, class="greek">μή rejects; class="greek">οὐ is absolute, class="greek">μή relative;class="greek">οὐ objective, class="greek">μή subjective.
ἀληθής "True" is from alethes, which means "unconcealed", "so true", "not forgetting", "careful," [of persons] "truthful" "honest," [of oracles] "true" "unerring," and [as adverb] "actually" "in reality,"