Is giving Foreign Aid legal, according to Constitution?

[Taso]

I thought I remembered Ron Paul saying that the Constitution does not grant the government the right to donate our tax dollars? I was reading through it, came to Article 1, Section 8, which states what the government CAN do with our tax dollars, which are meant for the "defense and welfare" of THIS country, not other countries.

Is there another article/amendment stating that tax dollars can be given to other countries?