I have sent six sons and one daughter on missions. For some reason, (probably because my wife hates it) it has always been my responsibility to write to them. I have done this faithfully every week, and have, at last count written about 700 letters to my children. All of these letters are evidence of my love, and almost all of them have contained doctrinal lessons intended to teach the gospel and to assist my children in dealing with the challenges and opportunities of their missions. Many times, I have responded to questions they have asked in their own epistles.
