To me the weak-kneed disciple is one who realizes that all the efforts of religion to somehow make and keep God happy with us are hopeless. To be weak-kneed is to look at yourself and see that you are unable to maintain the facade of competence as a Christian, to realize that hiding your sin from those around you is exhausting and powerless. To be weak-kneed is to come to Christ with EMPTY hands and plead for grace, and then to find the overflowing love of God for you, to hear the song of His delight in you.

I had surgery last year on my right knee. I walk with a constant pain/weakness that warns me that the knee can't really bear my weight. A constant reminder that I can't provide to God the strength to be His disciple, His son.