The inclusion of salt in the grain offering was linked to salt's preservative qualities. In the absense of their Egyptian Frigidaires, these travelers preserved their food supplies with salt. Salt in the grain offering signified the lasting nature of the covenant between Israel and Yahweh.
One of the attributes of humans is that we have long memories when someone offends us and short memories when we make a promise. As the years pass, our firm commitments seem to lose their significance and don't hold as much weight as they once did.
By adding salt to their offerings, the people of Israel were reminding themselves that they could trust God to keep his promises. And maybe God was reminding them that their promises were meant to be kept as well.
What promise will you keep this week?