One of the most common similarities across all of Christianity is the concept of baptism. Each denomination may do it differently, but there seems to be a sense of necessity present in every instance. Why is that? In the end, it comes down to the life and teachings of our Savior Jesus Christ. To start his public ministry, Christ traveled to John to be baptized in the Jordan River. Why John when there were many people in his day doing baptisms? The answer is because John had the authority from God to baptize. He could do it by God's power, in God's way. In addition to his example, Christ also taught, "He that believeth and is baptized shall be saved (Mark 16:16)." Baptism is an ordinance that is necessary for us to return to live with our Heavenly Father again.
In the Church of Jesus Christ of Latter-Day Saints, the authority to perform the ordinance of baptism has been restored. The same authority John the Baptist held. Through it, people can be baptized for the remission of sins and open the gate to eternal life with Heavenly Father. As missionaries we follow the Savior's command to "Go ye therefore, and teach all nations, baptizing them in the name of the Father, and of the Son, and of the Holy Ghost (Matt 28:19)."
So why baptism? Because "no unclean thing can enter into his kingdom; therefore nothing entereth into his rest save it be those who have washed their garments in my blood, because of their faith, and the repentance of all their sins, and their faithfulness unto the end (3 Ne 27:19)." Baptism and repentance are a gift. If we will utilize them to show our commitment and faith in Christ, we will be happy in this life and be able to dwell with him again hereafter.