The binding legal principles are: (1) "Municipal planning" in Part B of Schedule 4 of the Constitution includes the power to approve rezoning of land and the establishment of townships, not merely forward planning or conceptualization. (2) The functional areas in Schedules 4 and 5 must be interpreted purposively in a manner that enables each sphere of government to exercise its powers fully and effectively, consistent with the constitutional scheme of distinct, interdependent and interrelated spheres. (3) Section 156(1) read with Part B of Schedule 4 vests executive authority over municipal planning in municipalities. (4) "Urban and rural development" under Part A of Schedule 4 must be given a restrictive meaning and does not include powers forming part of municipal planning. (5) Provincial and national spheres may regulate the exercise of municipal executive authority under section 155(7), but may not themselves exercise those powers except through constitutionally prescribed interventions under sections 100 and 139. (6) Legislation that authorizes provincial organs to exercise powers falling within municipal planning is inconsistent with sections 156(1), 151(4), 155(7) and 41 of the Constitution. (7) The validity of pre-constitutional legislation must be tested against the 1996 Constitution, not the interim Constitution, as item 2 of Schedule 6 preserves old order laws only subject to consistency with the new Constitution. (8) A court has wide discretion under section 172(1)(b) to craft a just and equitable remedy, including suspending invalidity on conditions that balance legislative correction against practical consequences for administration and affected parties.