The key of the teaching comes after that metaphor, when the disciples ask how one can be saved and Jesus answers that “with man this is impossible, but with God all things are possible.”

These words eventually became the foundation of Christian charity in an Ancient world that until then despised and rejected the weak and infirm.

Many of our modern day institutions trace their origin to that Christian charity, to those few enigmatic words.

(Peter Brown's “Through the Eye of a Needle” is a great book to know more about this process.)