Here is the Haydock commentary on that verse and the one which followed:
Ver. 24. It is easier for a camel, &c. This might be a common saying, to signify any thing impossible, or very hard. Some by a camel, would have to be meant a cable, or ship-rope, but that is differently writ in Greek, and here is commonly understood a true camel. (Witham) --- But nothing is impossible to God.
Ver. 25. They wondered very much. The apostles wondered how any person could be saved, not because all were rich, but because the poor were also included, who had their hearts and affections fixed on riches. (St. Augustine and Nicholas of Lyra.)