Note: As the Church has said, the manual has been prepared as the primary source of lesson material. These supplements, from general conference addresses, are meant only as a complement to your study on this lesson’s topic.
Supplement is from Elder Dallin H. Oaks's talk, "Sacrament Meeting and the Sacrament" from the October 2008 general conference:
How can we have the Spirit of the Lord to guide our choices so that we will remain “unspotted from the world” (D&C 59:9) and on the safe path through mortality? We need to qualify for the cleansing power of the Atonement of Jesus Christ. We do this by keeping His commandment to come to Him with a broken heart and a contrite spirit and in that wonderful weekly meeting partake of the emblems of the sacrament and make the covenants that qualify us for the precious promise that we will always have His Spirit to be with us (see D&C 20:77).