The natural liberty is what Locke talks of when he refers to a person's right to be governed solely by natural laws. In this case to be under natural laws means to be absolutely free from any artificial authority or on earth or still to be under any will of man. The second liberty that Locke refers to indirectly in the chapter 4 of section 22 of the second treatise of government is what has come to be referred to as the social liberty.
Social liberty means that a person has a right not to be under any legislative power other the one that has been founded by the authority of the commonwealth, which in its part should be functioning for the benefit of that commonwealth. In this liberty the word commonwealth simply mean consent from the society itself which is in contrast with Filmer's egoistic approach to representation. It is important to note Filmer's obsession with the transference of authority to the monarchy which is essentially marks his divergence with Locke philosophy. Personal liberty is the third and last liberty that Locke alludes to in this excerpt which means that person ought not to be under any dominion whatsoever.