|Ambrogio Lorenzetti's "Madonna and Child" (1319)|
No one knows for sure why babies were salted or exactly how it was done. Some say salt was mixed with olive oil and the baby rubbed with it, others say the baby was washed with salted water, still others say a small amount of salt was rubbed onto the baby's skin. Too much salt will kill an infant so only a pinch of salt would have been used. The baby was then swaddled or wrapped with a long two to three inch band of cloth from head to foot in such a way that it held the joints straight. This was a symbolic gesture suggesting that the child would be raised to be upright before the Lord and would never be crooked or wayward. The babies were not left swaddled for long, but during the short time they were swaddled the parents would meditate and give thanks for the child entrusted to their care.
The reason for the salting of infants is just as debated as the practice, but from studying the significance of salt in the Law of Moses it is obvious that salt is a symbol of an everlasting covenant and of the honesty and integrity that should accompany any covenant with the Lord. Under the Law of Moses, every sacrifical offering was offered with salt. Therefore I side with those who think that the salting of babies had something to do with dedicating this new member of the House of Israel to the Lord. Thus Jesus, like all sacrificial offerings under the Law of Moses, was salted, and knowing that his atoning sacrifice would fulfill and end the law of blood sacrifice, He instructed that the new law would be that we are to be "the salt of the earth" (Matthew 5:13 and 3 Nephi 12:13).
What this means is that we are the covenant people of the House of Israel and thus we are to enhance, protect, preserve, endure, and sustain the covenant (the Good News!) that Jesus Christ made possible.