“Otherwise, what will they do who are being baptized for the dead, if the dead do not rise at all? Why then are they baptized for the dead?”—- 1 Corinthians 15:29 NKJV
Based on the scripture above, Mormonism teaches that its members have an obligation to research their genealogy and get baptized for any of their deceased relatives who were never baptized in the Mormon Church. The problem with this multifold, primarily:
(1) The scripture is not translated accurately. It should be translated as: “However, people are baptized because the dead will come back to life. What will they do? If the dead can’t come back to life, why do people get baptized as if they can come back to life” (1 Corinthians 15:29 GWT). This verse makes the point that getting baptized makes no sense if there is no resurrection.
(2) The context of 1 Corinthians 15:29 relates to the central issue of whether there is a resurrection or not. Creating a doctrine as unique as getting baptized for one’s deceased ancestors from one scripture stretches the bounds of credibility.
(3) One’s unbaptized dead ancestors are not alive anyway, so they have no ability even to know someone was baptized in their behalf, much less to “accept” such a proxy baptism. “The dead don’t know anything” (Ecclesiastes (9:5 GWT). “There is no work, planning, knowledge, or skill in the grave where you’re going” (Ecclesiastes 9:10 GWT). When a person dies, on “that very day his thoughts perish” (Psalm 146:4 NASB). “Who among the dead remembers you? Who praises you in Sheol?” (Psalm 6:6 NAB; 6:5 most).
(4) The Bible teaches: “Repent and be baptized, every one of you, in the name of Jesus Christ for the forgiveness of your sins” (Acts 2:38 NAB). Each Christian must be baptized for his or her own sins. No one else can do this for us. The Bible principle of individual accountability precludes any possibility that someone else could be baptized in our place. “We will all stand before the judgment seat of God. Each of us will give a personal account to God” (Romans 14:10,12 NLT).
(5) Any doctrinal developments using genealogies that goes beyond what is expressly written in Scripture is condemned by 1 Timothy 1:4; Titus 3:9 and 1 Corinthians 4:6. See the three article published on this site about genealogies. These Biblical principles definitely exclude any efforts to research one’s genealogy and then use such findings to get baptized as a proxy for any of one’s ancestors.