Commenting on Isaiah Berlin's four famous essays on liberty, but particularly his 1958 lecture titled "Two Concepts of Liberty," Os Guinness makes a few interesting observations:
Negative freedom, as Berlin defines it, is freedom from--in essence, freedom from interference and constraint. Positive freedom is freedom for--in essence, freedom for excellence according to whatever vision and ideals define that excellence.
...[I]n reality the choice between the two freedoms in never either/or. Negative and positive freedoms can be distinguished in theory, but if true freedom is to flourish, they must never be divorced in practice. Indeed, one of the most difficult challenges of the modern world is to create societies that allow diverse faiths and ideologies to have the maximum of both positive and negative freedoms for each faith and ideology. No nation has so far achieved full success in this test, though some have done better than others.
For one thing, neither positive nor negative freedom is complete without the other. They each describe complementary sides of the same full freedom, which always rests on two conditions: the complete absence of any abuse of power, which is the essence of positive freedom. In a free society understood in this way, free citizens are neither prevented from doing what they should (the denial of positive freedom) no forced to do what they shouldn't (the denial of negative freedom).1
1. Os Guinness, A Free People's Suicide: Sustainable Freedom and the American Future [Downers Grove, IL: InterVarsity Press; 2012] pp. 61-61