When God brought Israel out of Egypt, He did not take them directly to the Promised Land. Instead He began a process of teaching the former slaves how to be free. The first stage of the process took 50 days (seven sabbaths plus one day). That pattern is repeated in the Land, but in years instead of days. Every fifty years, Israel was to do a reset, restoring everyone to his patrimony, freeing all slaves and forgiving all debts. This teaches us that liberty is not easy and must periodically be refreshed.