For he (St. Francis) called the Rule the book of life, the hope of salvation, the marrow of the Gospel, the way of perfection, the key to paradise, the agreement of a perpetual covenant. He wanted it to be had by all, to be known by all, and he wanted it to speak everywhere to the interior man unto his comfort in weariness and unto a remembrance of the vows he had made. He taught them to keep it ever before their eyes as a reminder of the life they were to live, and what is more, that they should die with it.
He would tell his sons that she was the way of perfection, the pledge and earnest of eternal riches. No one was so greedy of gold as he of poverty; no one more careful in guarding a treasure than he in guarding this pearl of the Gospel.
~Thomas of Celano, The Second Life of St. Francis of Assisi