Display GAK 240 (Jesus the Christ).
Tell the story of Alma's repentance (see Mosiah 27).

Sing the second verse of "Help Me, Dear Father" (p. 99).
We can be forgiven just as Alma was.

Help the children memorize D&C 58:42 by writing three eight-letter words on the chalkboard:

Repeat the scripture several times, each time erasing one of the vertical columns of letters.

Tell the children that we have the story of Alma in the scriptures so that we can learn from his experience.
Explain, however, that the Lord no longer remembers the things that Alma did wrong. Or, to put it another way, "None of his sins that he hath committed shall be mentioned unto him" (Ezekiel 33:16).

Demonstrate repentance by showing a clear glass jar with water in it. (Depending upon the water in your area, you may need to add two tablespoons of vinegar to make the water clearer.)
Liken this clear water to us when we came to earth. We were pure and clean. When we make wrong choices and sin, we become impure. (Pour water colored with food coloring into the jar.)
But through the Atonement of Jesus Christ, we are able to repent, even as Alma did. (Pour bleach into the jar—water should return to clear if there wasn't too much coloring.)
Then we are pure and clean again.

Bear testimony of repentance.
To help children understand what it means to repent, refer to the Primary 3 manual, pp. 46–49.