A few weeks ago, I used a chain saw to cut down a tree in my backyard. It was a dirty job, and when I was done, I was splattered with a filthy mixture of sawdust and oil. In that condition I did not want anyone to see me. I just wanted to be cleansed in water so that I would again feel comfortable in the presence of other people.
Likewise, when we commit sin, we become spiritually unclean and the Spirit of the Lord withdraws from us. The Spirit of the Lord does not dwell in “unholy temples” (see Mosiah 2:36–37), and no unclean thing can dwell in His presence (see Moses 6:57).
No one lives without sin after his or her baptism, however. Without some provision for further cleansing, each of us is lost. How grateful we are that the Lord has provided a process for each baptized member of His Church to be cleansed from the soil of sin. The sacrament is an essential part of that process.
We are commanded to repent of our sins, to come to the Lord with a broken heart and a contrite spirit, and to partake of the sacrament. When we renew our baptismal covenants this way, the Lord renews the cleansing effect of our baptism. We are made clean and can always have His Spirit to be with us.