Thanks for the opportunity Non-Sequitur.
Article 1 Section 8: The Congress shall have the Power To ...Establish an uniform Rule of Naturalization...
Article 1 Section 8 the basis for the 14th Amendment, “All persons born or naturalized in the United States and subject to the jurisdiction thereof...” So the framers gave us Article 1 and, since they also provided the amendment process, they gave us the 14th Amendment, which some claim is redundant.
The 14th amendment is redundant with respect to white people, but not freed slaves. Under common law, children of slaves were not natural born subjects/citizens. In fact, they weren't subjects/citizens at all. Hence were it not for the 14th Amendment, freed slaves born in the USA to slave parents would not be US citizens. That's why it was necessary.