Can anybody explain what the "general welfare" is without saying what it is not?
We the people of the United States, in order to form a more perfect union, establish justice, insure domestic tranquility, provide for the common defense, promote the general welfare, and secure the blessings of liberty to ourselves and our posterity, do ordain and establish this Constitution for the United States of America.
The Congress shall have Power To lay and collect Taxes, Duties, Imposts and Excises, to pay the Debts and provide for the common Defense and general Welfare of the United States; but all Duties, Imposts and Excises shall be uniform throughout the United States;
welfare: exemption from any unusual evil or calamity; the enjoyment of peace and prosperity, or the ordinary blessings of society and civil government; applied to states.
Promote: To forward; to advance; to contribute to the growth, enlargement or excellence of any thing valuable.
(I got the definitions from the 1828 Webster’s dictionary because I did not want the modern definition of welfare and it is the one I found that's closest to the time the U.S. Constitution was written.)