The agreement of which the Evangelist speaks undoubtedly arose between the two mutually hostile parties of the scribes, that is, the learned men of the Jewish world, namely between the Pharisees and the Sadducees. We have already spoken of them more than once. Here we add only that, despite the sharp antagonism of opinion between these two parties in religious and philosophical questions, both parties supported ritual observance among the people with all their strength, though for different reasons.
They used it as a means of ruling the people despotically. They also apparently always acted in concert when it was necessary to establish and uphold the principle of the authority of the learned over “the accursed people,” as they called them. Compare Jn 7:49.
The age of which the parents of the man born blind speak was probably determined by those years of life at whose arrival marriage was permitted and even required. According to the Talmud, this was twenty years. In tractate Kiddushin, fol. 29, col. 2, it is said: “Beginning from twenty years, a man who remains unmarried remains in an unlawful state.”
Elsewhere it says: “A Jew who has no wife is not a man, for it is said in Gen 5:2: God created male and female... and called their name man.” These extracts are taken from Hershon's Genesis with a Talmudical Comment, London, 1883, pp. 123-124, nos. 27 and 39.
Nowhere in the Bible have we found any restriction on the right of young persons under thirty years of age to testify before a court. This latter opinion seems to be based on Numbers chapter 4, where it is established that Levites from thirty to fifty years old were taken for the service of the Lord in the Tabernacle. But we note that younger and older men were left at home for their household work.
Therefore we cannot say that the man born blind was at least thirty years old when he was brought before the assembly. Thus Bishop Michael, p. 335. Chrysostom explains that, when the parents speak of their son's age, they mean only to say: he is not a child, not a minor, and can testify about himself. Homily 58 on John, part 2, p. 138. Theophylact says the same on this passage of John.