Legal Question in Constitutional Law in Florida

Although your question is not entirely clear, I presume you are asking why the federal income tax is constitutional.

The language you cite was part of the original Constitution that was enacted in 1787. In 1913, however, the Constitution was amended so that it now expressly allows an income tax. The 16th Amendment states that "The Congress shall have power to lay and collect taxes on incomes, from whatever source derived, without apportionment among the several states, and without regard to any census or enumeration."

I also want to point out the context of the section you cite from the original Constitution. Article 1, section 8, clause 1 says "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." That clause gives Congress the power to collect for different types of income and then says that three of those four must be uniform throughout the country. The fourth form -- and thus, by implication, the one that need not be uniform nationwide -- is taxes.