According to the US Constitution, memmbers of the House only have to be residents of the state in which the district is located. I assume the Framers deemed it wouldn’t be necessary to make it a requirement due to the fact that no one would vote for someone to represent them who “wasn’t on of them”.
I may be wrong about this, but I believe that in some states, the elections for the House of Representatives in the early days of the U.S. were all done for the entire state and there were no “districts” to speak of. If a state had 10 House districts, they had ten candidates running for the House on a statewide basis.