Definition: A rite signifying a believer's cleansing from sin through Christ's atoning death. The Illustrated Bible Dictionary, George W. Knight, p. 42.
Baptism is a cleansing practice; and more importantly, is not required for Salvation according to the Bible.
None of them can by any means redeem his brother,
Then they said to Him, "What shall we do, that we may work the works of God?" Jesus answered and said to them, "This is the work of God, that you believe in Him whom He sent."
There is one body and one Spirit, just as you were called in one hope of your calling; one Lord, one faith, one baptism; one God and Father of all, who is above all, and through all, and in you all.
Interestingly, the Book of Mormon agrees with the Bible, yet the Doctrine and Covenants disagrees with the Bible and the BoM.
Moroni 8:22-23 - agrees
For behold that all little children are alive in Christ, and also all they that are without the law. For the power of redemption cometh on all them that have no law; wherefore, he that is not condemned, or he that is under no condemnation, cannot repent; and unto such baptism availeth nothing - But it is mockery before God, denying the mercies of Christ, and the power of his Holy Spirit, and putting trust in dead works.
D&C 128:5 - disagrees
You may think this order of things to be very particular; but let me tell you that it is only to answer the will of God, by conforming to the ordinance and preparation that the Lord ordained and prepared before the foundation of the world, for the salvation of the dead who should die without a knowledge of the gospel.
D&C 128:17-18 - disagrees
And again, in connection with this quotation I will give you a quotation from one of the prophets, who had his eye fixed on the restoration of the priesthood, the glories to be revealed in the last days, and in an especial manner this most glorious of all subjects belonging to the everlasting gospel, namely, the baptism for the dead; for Malachi says, last chapter, verses 5th and 6th: Behold, I will send you Elijah the prophet before the coming of the great and dreadful day of the Lord: And he shall turn the heart of the fathers to the children, and the heart of the children to their fathers, lest I come and smite the earth with a curse. I might have rendered a plainer translation to this, but it is sufficiently plain to suit my purpose as it stands. It is sufficient to know, in this case, that the earth will be smitten with a curse unless there is a welding link of some kind or other between the fathers and the children, upon some subject or other - and behold what is that subject? It is the baptism for the dead. For we without them cannot be made perfect; neither can they without us be made perfect. Neither can they nor we be made perfect without those who have died in the gospel also; for it is necessary in the ushering in of the dispensation of the fulness of times, which dispensation is now beginning to usher in, that a whole and complete and perfect union, and welding together of dispensations, and keys, and powers, and glories should take place, and be revealed from the days of Adam even to the present time. And not only this, but those things which never have been revealed from the foundation of the world, but have been kept hid from the wise and prudent, shall be revealed unto babes and sucklings in this, the dispensation of the fulness of times.
D&C 84:74 - disagrees
Verily, verily, I say unto you, they who believe not on your words, and are not baptized in water in my name, for the remission of their sins, that they may receive the Holy Ghost, shall be damned, and shall not come into my Father's kingdom where my Father and I am.
In contrast to what the Bible teaches, the LDS church teaches us that baptism is one of the many requirements for entering heaven and the temple.
4th Article of Faith
We believe that the first principles and ordinances of the Gospel are: first, Faith in the Lord Jesus Christ; second Repentance; third, Baptism by immersion for the remission of sins; fourth, Laying on of hands for the gift of the Holy Ghost.
In the LDS church, children make the baptismal commitment at age eight. I never thought anything odd of this until a friend helped me realize there is no way an eight year old child could make the type of commitment the LDS church requires at baptism. He recalled when he reached the age of confirmation. He had no idea what this was all about. He was so grateful he did not follow the seven sacraments as Catholics should do. If he did not get it at age twelve, and I didn't get it until I was 34, then how is an eight year old child expected to get it?
BAPTISM FOR THE DEAD, from mormoninfo.org
LDS church: Baptism for the dead is required.
Baptism in place of the dead is an essential ordinance done in LDS temples on behalf of those who died not receiving the benefit of LDS baptism (Gospel Principles, 255-62 [1997 edition]). Joseph Smith said, "The greatest responsibility in this world that God has laid upon us is to seek after our dead" (Fielding Smith, The Teachings of the Prophet Joseph Smith, 356 [pre-2002 edition]).
Christianity: Baptism for the dead is not required.
The only biblical passage that mentions baptism for the dead was most likely done by those outside of Christianity, since the Apostle Paul made a contrast between what "they" do and what "we" do. Paul said that even those who do baptism for the dead believe in the resurrection. How much more should we, who do not baptize for the dead and are led by apostles who were eyewitnesses of Christ's resurrection, believe in the resurrection (1 Corinthians 15:29-30). Even if some of the Corinthians were performing baptisms for the dead, there is no reason to think the practice was understood to be a means of salvation. Further, even though baptism is normal and a believer should be baptized, it is not essential for salvation (e.g., Acts 10:44-48). Finally, there is no second chance for salvation to those who reject it in this life (Luke 16:19-31; and Hebrews 9:27).
My unanswered question was:
If baptism is required for salvation, then why did Christ never baptize anyone?
I was initially devastated when I received this answer that baptism is not required for salvation, yet overjoyed to find the truth that Christ has saved me from my sins by dying on the Cross for me! All I have to do to be saved is believe in the Lord Jesus Christ!