When you priests of the Aaronic Priesthood administer the sacrament, you are doing what Jesus did while He was yet in the flesh, and which He also did when He ministered among the Nephites following His resurrection.
When you, as a priest, kneel at the sacrament table and offer up the prayer, which came by revelation, you place the entire congregation under covenant with the Lord. Is this a small thing? It is a most important and remarkable thing.
Now, my dear young brethren, if we are to enjoy the ministering of angels, if we are to teach the gospel of repentance, if we are to baptize by immersion for the remission of sins, if we are to administer to the membership of the Church the emblems of the sacrifice of our Lord, then we must be worthy to do so.
You cannot consistently so serve on the Sabbath and fail to live the standards of the Church during the week. It is totally wrong for you to take the name of the Lord in vain and indulge in filthy and unseemly talk at school or at work, and then kneel at the sacrament table on Sunday. You cannot drink beer or partake of illegal drugs and be worthy of the ministering of angels. You cannot be immoral in talk or in practice and expect the Lord to honor your service in teaching repentance or baptizing for the remission of sins. As those holding His holy priesthood, you must be worthy fellow servants.