Pass the Salt
The beginning of the third book of the Torah, the book of Leviticus, discusses many categories of offerings, elaborating on the details of each of the various offerings. One law that applies equally to all offerings is that every offering must be offered with salt, as emphasized in the verse:
And you shall salt every one of your meal offering sacrifices with salt, and you shall not omit the salt of your God's covenant from [being placed] upon your meal offerings. You shall offer salt on all your sacrifices. (Leviticus 2:13)
This verse is also the source of the custom to dip our bread in salt, as explained in the code of law:
it is customary to place salt on the table [before the recitation of the blessing HaMotzi, even when the bread does not require it. The rationale is that] the table is comparable to the altar [of the Beis HaMikdash] and our food, to a sacrifice, and it is written: “On all your sacrifices offer salt.” (Shulchan Aruch Harav, Orach Chaim chapter 167)
Why salt?
When a Jew would be inspired to ascend to Jerusalem, come to the house of G-d and offer a sacrifice as a symbol of his bringing himself closer to G-d, the Torah instructs him to pour salt on the offering. In the ancient world salt was the primary preservative agent. Salt, therefore, is a symbol of preservation. Before the era of modern refrigeration, the symbolism of salt was clear. With the commandment that no offering be brought without salt, the Torah is teaching a Jew that there is no value to a fleeting moment of inspiration. When one is inspired to come close, to offer an offering, one must seize the flash of inspiration, and preserve it by sprinkling it, figuratively speaking, with a measure of salt. One must seek to internalize the inspiration, the desire to change and improve, to the point that it is integrated within one’s identity.
There is more to the symbolism of salt.
Everything physical is, by definition, temporary and fleeting. Every experience, everything we work so hard for, is but temporary. The only thing that is eternal is the spiritual aspect of life. Say you go out for dinner or you take a family vacation. The physical aspects of the experience are fleeting and will be gone before you know it. But there is a way to make the experiences everlasting. If the dinner deepens your connection to your spouse, if the vacation allows you to bond with your child, if the experience helps you get in touch with your soul, then you preserved it for eternity.
This is the symbolism of the salt on the sacrifices.
The Torah is teaching us that we can take a physical object, temporary and fleeting and make it lasting and immortal. We can and should salt our offerings, infuse them with spirituality which is the true preservative. When we eat a meal, and the same is true of any other physical experience, we can either engage in the material, temporary, aspect of the experience, or we can dip our bread in salt. We can transform the experience and make it one that is spiritual, holy, and everlasting.