The two functions of Government

The two functions of Government are as follows and are only these:

i) The Government should make sure that the Lockean Proviso is being observed and that "...there was still enough and as good left, and more than the yet unprovided could use."; that people are not restricted from (legitimate) access to resources by an entity that does not have sufficient claim to them.
ii) The Government should make sure that people are able to have access to a free market at all times, unburdened by tariffs, taxes and (illegitimate) barriers to entry.

If the Government follows these two rules and provides for its citizens access to resources and a free market, then it can do no more than that. The Government is not able to make sure the people are safe and provided for if they themselves are not able to accomplish the task, and if anything is a luxury, ie not essential, then what justification is there for it be imposed by force?