John Lightfoot on Matthew 19:24

[A camel to go through the eye of a needle, &c.] A phrase used in the schools, intimating a thing very unusual and very difficult. There, where the discourse is concerning dreams and their interpretation, these words are added. They do not shew a man a palm tree of gold, nor an elephant going through the eye of a needle. The Gloss is, "A thing which he was not wont to see, nor concerning which he ever thought."

In like manner R. Sheshith answered R. Amram, disputing with him and asserting something that was incongruous, in these words; "Perhaps thou art one of those of Pombeditha, who can make an elephant pass through the eye of a needle": that is, as the Aruch interprets it, "who speak things that are impossible."