I found this little account by the prophet delightful. Joseph Smith was asked to expound Matthew 23:37, but said he never had much to say when asked to expound a scripture. His reason was that a man who has the key can open it in a moment, whereas a man who is trying to hack his way around the lock must spend considerable time and effort.
From Teachings of the Prophet Joseph Smith (pg 307):
He then took for his text the 37th verse of 23rd chapter of Matthew–“O Jerusalem, Jerusalem, thou that killest the prophets and stonest them which are sent unto thee; how often would I have gathered thy children together, even as a hen gathereth her chickens under her wings, and ye would not.”
This subject was presented to me since I came to the stand. What was the object of gathering the Jews, or the people of God in any age of the world? I can never find much to say in expounding a text. A man never has half so much fuss to unlock a door, if he has a key, as though he had not, and had to cut it open with his jack-knife.