One of a little 7 year old Megumi praying for friends, being the only primary child in our group, she told her Mom she need friends, her angel mother told her to pray, then a month later me and Edler Rees on the street ran into a member mother who had just moved here with two kids her age, answering a child's prayer.
Another of a woman, Kishida san who was able to learn and gain a testimony of the savior and the Book of Mormon and had a desire to be baptized, but her health was too bad to go all the way to Hiroshima so she feared she couldn't, but then me and a member gave her a priesthood blessing, and she miraculously felt better than she ever had in a long time, and was able to happily and healthily go to Hiroshima and asked me to baptize her.
When I heard both these stories the spirit impacted me so powerfully, almost as if it was a voice saying, "You were an instrument in His hands."
And then a profound feeling joy, and also of humility swept over me. In all those stories it was really nothing I did, I was just there, yet God had used me to answer the prayers of His children. I truly understand Ammon, joying to be an instrument in the hands of The Lord. Joy in missionary work doesn't come from "being so good missionaries that we get the most baptisms." But it truly comes from that joy we can feel, when we know we faithfully served Him, and were instruments in His hands in blessing his children.