Elder Bednar's talk is a great read for getting into the spirit and knowledge of this song.
I want the kids attention for the message of this song, because it is a deep message and an important one. I am bringing a cut up chain of people labeled: Me, Dad, Mom, Grandma, Grandpa, Great Grandpa, Great-great Grandpa, Great-great-great Grandpa. I will tell the kids as they are quiet and sing well, I will start to connect the family with tape and seal them together, like when families get sealed in the temple. If all the family is together by the end I will give the kids a treat. (I bought Starburst $1.98 for a pack of 80 at Walmart--definitely worth it for an attention grabber!).
The hearts of the children turn to their fathers: Deep inside you will feel the need to find your ancestors and do their temple work.
So for this part of the song we will make heart shapes on our chest. While holding that pose, turn to side of room where black and white picture of an older couple is. Explain the picture represents your grandparents, and great grandparents and great, great grandparents and so on.
Malachi prophesied their hearts shall turn: Hold up a bible and tell children that Malachi was a prophet before Jesus was on the earth. He said that Elijah would come to bring the sealing power and your heart would feel love for your ancestors.
Sign the word prophesy then do the same heart on chest and turn to picture.
Elijah fulfilled the prophesy: Show children picture of Kirtland Temple and tell them Elijah came to Joseph Smith and Oliver Cowdery in the Kirtland Temple and gave them the power to seal families. Here's a good article from The Friend on this story.
We read in the bible that Elijah didn't die, he was taken up to heaven in a cloud. So for this action we will raise our hands in the air (palms up) like Elijah went up into heaven. Then we'll lower our hands again because Elijah came down and appeared to Joseph Smith.
And families can be sealed for eternity: You can be with your families forever, even after you die because of this sealing power. Bear testimony about this.
Sign word for families and eternity. I will sign families so that my pinkies touch while singing sealed. I will sign eternity so that the first circle with my pointer finger goes while singing "eter-", pointer goes around the second time while singing, "-ni-", and pinky pointing out for, "-ty."
Sing song a few times with actions.
Maybe sing one time where they turn around on words starting with the letter "F": Fathers, fulfilled, families.