John 1:7

οὗτος ἦλθεν εἰς μαρτυρίαν … δι αὐτοῦ. “The same (or, this man) came for witness,” etc. “John's mission is first set forth under its generic aspect: he came for witness; and then its specific object (ἵνα μαρτ. περὶ τ. φ.) and its final object (ἵνα παντ. πιστ.) are defined co-ordinately,” Westcott. John was not to do a great work of his own but to point to another. All his experience, zeal, and influence were to be spent in testifying to the true Light. This he was to do “that all might believe through him”. The whole of this Gospel is a citing of witnesses, but John's comes first and is of most importance. At first sight it might seem that his mission had failed. All did not believe. No; but all who did believe, speaking generally, believed through him. The first disciples won by Jesus were of John's training; and through them belief has become general.