To do so requires negotiation with the Palestinian Leadership and the UN. Israels legal borders are still those as defined by Resolution 181 IN 1948 which it accepted and agreed to. Internationally it was recognised on those borders. That is its ONLY sovereign territory. All the rest belongs to Palestinians. Maybe when your illegality costs you enough maybe then you will return within your legitimate borders. It is already costing you...look at your deficit and watch it grow.
Austrian chancellor: Austria and Germany will allow migrants entry (Reuters)