There are many reasons why we can experience energy field intrusions, and there are many different types of intrusions - from cords, to foreign energies, to thoughtforms. In order to prevent our energy field from being infiltrated by energetics that do not belong to us, it's important to create strong energetic (and physical) boundaries and resolve energies that create porosity in our energy body. This takes time and is a process that unfolds through deep personal healing.
While we focus on deep inner healing work and soul-alignment practices, it is important to have tools to protect our energy field in situations where we might still experience energy field instrusions before the root energetic cause of these intrusions is resolved. The S.A.R.A. symbol for energy field strengthening from Initiation 1 can be used for protection in this way.