My friend's son was called to serve a mission in Brazil. Both their son and his parents were so ecstatic about where he'd be assigned. Every week he'd write them letters and tell them how great his first area was, then his second area and how wonderful his companion, then this next companion, and how the testimonies of the local leaders, members and converts are helping him strengthen his own. He also mentioned as to how amazing he's learning the new language way fast that most of his colleagues.
Then the next week came his letter asking them his Line of Authority card and important it was for him for their next discussion with an investigator who wants to know how he got his authority to teach them the restored gospel. His parents, not exactly knowing what a Line of Authority is, referred the matter to me and wonder if my kids have one. Well, I told them my little boys have theirs since my boys are the only ones with priesthood authorities. It's their special link back to the Savior Jesus Christ. Now you might be wondering how could you obtain your priesthood line of authority card? Others are also worried that they might not be able to find their records in the archive. The Lord promised in the holy writ that those who seek shall find while those who knock will be opened doors. Resolve within yourself to find such a vital information and the Holy Ghost shall be your guide in the whole process.