Book of Days-Sept 9: confusing term in text

[Cecile]

3rd paragraph of Book of Days for Sept 9:  "Many times it is the one who is unassuming and humble, who accepts the basic unworthiness of free will while recognizing the necessity of it, who may choose and choosee and choose again the way of love, the way of Christ."

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Can somebody explain to me the "basic unworthiness of free will"? 
1) Unworthy of what? 
2) Why is free will unworthy? 

Cecile