“Gathering together” (NASB) is literally “took salt together,” an idiom for table fellowship. This act was the ultimate sign of physicality and intimacy.” Salt on the table is a covenant symbol.  The table in the ancient near eastern mindset is considered to be like an altar.  Therefore, having salt on the table would be a fitting covenant symbol to have.

… in Luke 12, Yeshua begins to share with them about confessing that He is the Messiah, the Son of Elohim before men.  This in turn will cause them to be brought before the leaders with much persecution.  Yeshua counsels them ahead of time that they are not to be given to worry.