"If I testify about myself, my witness is not valid.
my witness is not true, לא נאמן, not to be believed, or admitted as an authentic testimony: and so the Ethiopic version renders it, "is not credible"; not valid in law, or in such a court of judicature in which Christ now was; for, as according to the Jewish law, no man was admitted a witness for himself, so neither was anything established by a single testimony, but by the mouth of two or three witnesses, Deuteronomy 19:15. Christ's meaning is, that his testimony alone, his single witness, how true soever it was, would stand for nothing in their court; and therefore he would not insist upon it, but drop it; for "true" here, is not opposed to that which is "false", but to that which is not valid in law. Christ's testimony was true in itself; nor could it be any other, it coming from him, who is truth itself, the "Amen", and faithful witness; but being considered as an human testimony, and in his own cause, was not to be admitted as sufficient; and this he allows. From arguments, proving his equality with the Father, he passes to testimonies; and without ranking use of his own, he had enough to produce, and which were valid and authentic, and are as follow.