It has probably come within the observation of many persons, that there is a form or modification of religious experience, which is denominated "Liberty." Hence in common religious parlance, it is not unfrequently the case that we hear of persons being "in the liberty," or in the "true liberty." These expressions undoubtedly indicate an important religious truth, which has not altogether escaped the notice of writers on the religious life. The account, which is given by Francis de Sales of "liberty of spirit," is, that "it consists in keeping the heart totally disengaged from every created thing, in order that it may follow the known will of God."
To this statement of De Sales, considered as a general and somewhat indefinite statement, we do not find it necessary to object. Certain it is that he, who is in the "true liberty," is "disengaged," and has escaped from the enslaving influence of the world. God has become to him an inward operative principle; without whom he feels he can do nothing; and in connection with whose blessed assistance he has an inward consciousness, that the world and its lusts have lost their enthralling power. Liberty, considered in this general sense of the term, is to be regarded as expressive of one of the highest and most excellent forms of Christian experience. And we may add further, that none truly enjoy it in this high sense but those who are in a state of mind, which may with propriety be denominated a holy or sanctified state; none but those whom God has made "free indeed." We proceed now to mention some of the marks, of which the condition or state of true spiritual liberty is characterized. Nor does there seem to be much difficulty in doing this, because liberty is the opposite of enthrallment; and because it is easy, as a general thing, to understand and to specify the things, by which we are most apt to be enthralled.
The person, who is in the enjoyment of true spiritual liberty, is no longer enthralled to the lower or appetitive part of his nature. Whether he eats or drinks, or whatever other appetite may claim its appropriate exercise, he can say in truth, that he does all to the glory of God. It is to be lamented, but is, nevertheless, true, that there are many persons of a reputable Christian standing, who are subject, in a greater or less degree, to a very injurious, tyranny from this source. But this is not the case with those, who are in the possession of inward liberty. Their souls have entered into the pleasures of divine rest. And they can truly say they are dead to all appetites, except so far as they operate to fulfill the original and wise intentions of the Being who implanted them.
— edited from The Interior or Hidden Life (1844) Part 2, Chapter 14 by Thomas Cogswell Upham. You can find more of his work at the blog, The Hidden Life, managed by Craig L Adams at: http://thomascupham.blogspot.com