The constitution says NOTHING about civilians carrying concealed firearms, nor does it say you can keep them to defend your property from burglars. What it does say is that the population have the right to keep and bear arms such that they can, when necessary, form an organised militia. It is the LAW, depending on which State you are in, that governs the right to own and carry firearms, and how you might do so.
This wording for the 2nd Amendment was based on the English Bill of Rights, 1689, which includes the text "That the Subjects which are Protestants may have Arms for their Defence suitable to their Conditions and as allowed by Law"