Salt is just a mere representation of what human acts should be towards others. Since salt brings out the best flavours in any dish, so must we with our attitude towards others

Matthew 5:13: Salt is valuble anduseful, but if it has no flavor, it is of no use, might as well just throw it on the ground. If you do not have your Savior, although man is king of all beast over the earth, he is of no use. You need your Savior to be complete.

Luke 14:34-35 : This passage is essentially saying the same thing. Salt is of no good without flavor, and manis of no good without his faith.

Sometimes it helps to read a few before of after the passage you are trying to decipher to determine the context it should be taken in. Parables can be helpful, but often they take some thought as well.