Claim. Because True Parents fulfilled all four stages of the curriculum, loyalty paid to them counts as loyalty to God; attending True Parents is the substantive form of attending God.
Elaboration. SMM stitches the True Parents into the four-stage scheme: “The True Parents are the ones who have fulfilled the traditional duties of children of filial piety in the family, patriots or loyal subjects in the nation, saints in the world, and divine sons and daughters in heaven and earth. Without such a concept, you cannot stand before God as the filial child that He desires in the family or as the patriot that He desires in the nation… or as the saint that He desires in the world; and you cannot attend the divine son, who can become the filial son of heaven and earth” (CSG 14.7 §2, 266-145, 1994.12.22). The argument is that True Parents are the historic instantiation of the complete curriculum, so loyalty given to that completed standard is structurally the same as loyalty to the heavenly Father standing behind it.
See also. csg-six-thousand-years-without-a-true-loyal-subject · csg-attending-true-parents-confers-filial-qualification