One's virtues must be renewed daily

To attain the promises of God, we need above all continuous exercise in the virtues; for however firm one’s commitment to some good may be, if it is not renewed daily, it quickly dies out.

- John Trithemius
as quoted on God's Politics
http://blog.beliefnet.com/godspolitics/2007/09/voice-of-the-day-13.html