"Liberty" is when you can do what you want without interference from people you didn't ask for.
A few examples: People can't take things that are yours, can't kill you, threaten you, enslave you.
If you make a voluntary contract with someone to give him something or do something for him, in exchange for his giving you something or doing something, then you are obliged to carry out your part of the deal as he must carry out his part, because you both agreed to. The sanctity of contracts is very important, because without it there can be no reliable cooperation or long-term planning. Getting out of a contract is unusual, but shiite happens, and you can get out if you both agree.
If you want to help someone who's having hard time (charity), you certainly can. And if you want to talk others into doing the same, you (and they) can certainly do that too. But you are not obliged to, and neither are they.
Government's job is to make sure someone you didn't ask for, doesn't interfere with you. Aside from that, you're on your own. Govt doesn't owe you food, shelter, health care, or anything else but protection. And it has no business telling you how you must get those things, as long as you don't interfere with others who didn't ask for your "help".