From today's gospel:

[Mt 23-26] Jesus said to His disciples, "Truly, I say to you, it will be hard for a rich man to enter the Kingdom of Heaven. Again I tell you, it is easier for a camel to go through the eye of a needle than for a rich man to enter the Kingdom of God." When the disciples heard this they were greatly astonished, saying, "Who then can be saved?" But Jesus looked at them and said to them, "With men this is impossible, but with God all things are possible."

I've heard that "the eye of the needle" was a gate through which the camel had to be unloaded in order to pass, and that the hearers would have understood this. But if they understood it this way, why the astonishment, who then can be saved?

perhaps it is a double entendre, because he doesn't say, "the eye of the needle" (the gate in question) but "the eye of a needle" (a very small thing indeed!)