Apart from its obvious use in cooking, salt was widely used in the ancient world to keep perishable foods from decay (Leviticus 2:13; Job 6:6). Because of salt’s uses and characteristics, the Bible refers to it to illustrate aspects of the lives of Christians. Just as salt gives food a good taste, so the gracious qualities of their new life in Christ should make the speech of Christians wholesome and pleasant (Colossians 4:6). If they are living as they should, Christians will be a good influence in a world corrupted by sin (Matthew 5:13; Mark 9:50).
Because of its use in flavouring and preserving, salt symbolized a close and permanent relationship between people. It had a ceremonial use in making covenants, where it symbolized the unbroken loyalty that the two parties promised to the covenant (Leviticus 2:13; Numbers 18:19; 2 Chronicles 13:5; see COVENANT).
Sometimes, however, salt symbolized judgment and desolation. This was because salty land was useless for farming and became a barren waste. Therefore, a conqueror may have sprinkled salt over a destroyed city to symbolize that it was to be left in permanent desolation (Deuteronomy 29:23; Judges 9:45; Jeremiah 17:6; Zephaniah 2:9).
The Israelites obtained their salt mainly from the region around the Dead Sea, which was itself so rich in salt that it was sometimes called the Salt Sea (Genesis 14:3; Joshua 3:16; Joshua 15:5; Joshua 18:19). Somewhere to the south-west of the Dead Sea, in the dry region of Israel known as the Negeb, was a place called the Valley of Salt (2 Samuel 8:13; 2 Kings 14:7). (For further details of the Dead Sea and the Negeb see PALESTINE.)