John Chrysostom
Catena Aurea · Johannesevangelium 8
Then said Jesus to those Jews which believed on him, If ye continue in my word, then are ye my disciples indeed; And ye shall know the truth, and the truth shall make you free. They answered him, We be Abraham’s seed, and were never in bondage to any man: how sayest thou, Ye shall be made free? Jesus answered them, Verily, verily, I say unto you, Whosoever committeth sin is the servant of sin. And the servant abideth not in the house for ever: but the Son abideth ever. If the Son therefore shall make you free, ye shall be free indeed.
(Aug. [Chrys. Nic.] Hom. liv. 1) Our Lord wished to try the faith of those who believed, that it might not be only a superficial belief: Then said Jesus to those Jews which believed on Him, If ye continue in My word, then are ye My disciples indeed. His saying, if ye continue, made it manifest what was in their hearts. He knew that some believed, and would not continue. And He makes them a magnificent promise, viz. that they shall become His disciples indeed; which words are a tacit rebuke to some who had believed and afterwards withdrawn.