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 Robert D. Hales's talk, "Blessings of the Temple" from a Brigham Young University devotional address:
The temple endowment blessings are as essential for each of us as was our baptism. For this reason we are to prepare ourselves that we may be clean to enter the temple of God.
The opportunity to enter the temple and to take upon ourselves the sacred covenants therein is one of the greatest blessings available to us in mortality. Then, after we take upon us those covenants, our obedience in living them daily stands as a demonstration of our faith, love, devotion, and spiritual commitment to honor our Heavenly Father and His Son, Jesus Christ. Our obedience also prepares us to live with Them in the eternities. The temple’s saving ordinances are essential to—and even the central focus of—the eternal plan of happiness [...]
The primary purpose of the temple is to provide the ordinances necessary for our exaltation in the celestial kingdom. Temple ordinances guide us to our Savior and give us the blessings that come to us through the Atonement of Jesus Christ. Temples are the greatest university of learning known to man, giving us knowledge and wisdom about the Creation of the world. Endowment instructions give guidance as to how we should conduct our lives here in mortality. The meaning of the word endowment is “gift.” The ordinance consists of a series of instructions on how we should live and covenants we make to live righteously by following our Savior.
Another important ordinance is being sealed for eternity in celestial marriage. This covenant of marriage allows children to be sealed to their parents and children born in the covenant to become part of an eternal family.
The Doctrine and Covenants teaches us: “Whatsoever you seal on earth shall be sealed in heaven; and whatsoever you bind on earth, in my name and by my word, saith the Lord, it shall be eternally bound in the heavens” (D&C 132:46).
When a couple is kneeling at the altar, as a sealer I am aware of my role as a representative of the Lord. I know that what is sealed on earth is literally sealed in heaven—never to be broken if those being sealed remain faithful and endure to the end.