The chief objective for liberalism is human freedom … with reasonable limits. ‘Freedom’ means the ability to do what one wills with one’s own life and property. Liberals differ from Anarchists in that they believe that people need to be ‘oppressed’ by governments in order to be free in other respects — though they value government only for the freedom it brings, and don’t consider it something valuable or desirable in itself. Classical Liberals contend that government should only police the country and prevent interference from foreign governments because this allows people the maximum amount of freedom (negative freedom), whereas Modern/Social Liberals say that government must proactively give freedom to its citizens by making sure they’re not oppressed or disadvantaged or dying (positive freedom).
Also, as far as Classic Liberals are concerned, Liberalism has nothing to do with equality. Modern Liberals disagree on the grounds that an unequal society is an unfree society for the majority of poor and disadvantaged individuals — whom their rich and privileged minority counterparts are free to oppress if the government doesn’t protect them.
There have been some splits in liberalism over time. The first important split is the one between natural-law liberalism and utilitarian liberalism. Natural-law liberalism holds that humans, due to divine or natural law, have certain rights that no government should infringe upon. These rights are due to self-ownership, meaning that you own yourself, and no other human does (though you may belong to God, according to early liberals, you do not belong to any other person). John Locke was a major proponent for this view, which was also influential in The American Revolution.
Utilitarian liberalism grew in popularity in the 19th century, and it holds that the best course of action is to pursue what would bring the greatest happiness to the greatest number of people. Since only the individual knows what would bring the greatest happiness to himself or herself, then governments should pursue a policy of personal autonomy, letting everybody pursue their own happiness. The most influential advocate for utilitarian liberalism is John Stuart Mill.
The other great split is between classical liberalism and left-liberalism. The split between classical liberalism and left-liberalism (also known as social liberalism) is arguably due to different concepts of rights. To the classical liberals, rights are nullifications of the power of the State* (i.e. the ability to legitimately initiate the use *of force), meaning no individual or groups thereof can use force, fraud or threats thereof to stop any other individual from performing a specific action. For instance, if you have the right to free speech, this means that no individual or institution can start or threaten the use of force or fraud against you in order to stop you from speaking in a specific way (provided, of course, said speech constituted neither fraud nor coercion).
To social liberals, rights are seen as entitlements to the ability to perform specific actions. For instance, if you have the right to education, this means that other people (or groups thereof) must act in order to provide you an education if you cannot provide it yourself.
So, to classical liberals, rights are things others cannot use force to stop you from doing, and to social liberals, rights are things that others must enable you to do. Isaiah Berlin referred to the former as “negative liberty” and the latter as “positive liberty.”