The name of “rich” he here gives to one who covets temporal things, and boasts himself in them. To such rich men are opposed the poor in spirit, of whom is the kingdom of heaven. Now mystically it is easier for Christ to suffer for the lovers of this world, than for the lovers of this world to be converted to Christ. For by the name of a camel He would represent Himself: for He voluntarily humbled Himself to bear the burdens of our infirmity. By the needle He signifies sharp piercings, and thereby the pangs received in His Passion, but by the form of the needle He describes the straitening of the Passion.
Reproduced in full. Translation: Oxford 1841 (Newman), public domain (Public domain).
Also cites: de Quæst Evang. lib. ii. c. 42.