When asked, ‘what is the most important commandment?,’ Harold B. Lee responded,

“The most important of all the commandments of God is that one that you’re having the most difficulty keeping today. If it’s one of dishonesty, if it’s one of unchastity, if it’s one of falsifying, not telling the truth, today is the day for you to work on that until you’ve been able to conquer that weakness. Then you start on the next one that’s most difficult for you to keep.” 

Church News, May 5, 1973, p. 3