In the early days of the Church the practice of “re-baptism” was often performed. This was a renewal of one’s baptismal covenant. The practice was eventually discontinued, and these comments by George Q. Cannon, First Counselor in the First Presidency reveals the attitude that Church leaders had towards the role of repentance and baptism:
“We hear a good deal of talk about rebaptism, and the First Presidency and the Twelve have felt that so much rebaptism ought to be stopped. Men, when they commit sin, think if they can only get the Bishop to re-baptize them, they are all right and their sins are condoned. It is a fallacy; it will lead to destruction. There is no such thing in the Gospel of the Lord Jesus Christ. It is repentance from sin that will save you, not re-baptism.” (In Conference Report, Oct. 1897, p. 68.)
I believe this illustrates an understanding that baptism, while necessary, is only a ceremonial act that symbolizes the most important aspect of covenant making: repentence. While some critics of Mormonism might consider baptism a “work”, they should note that LDS intimately link baptism with repentence, which can hardly be called a “work” that earns salvation.