This is Father's direction for the whole world, and He has not changed this standard. Man perfects himself by going through a growth period. So we need to receive 7 days of truth in order to be re-created. There was a time when Father could only witness to elderly people. The Messiah is for all people.
Old people can witness to middle aged people, who can then witness to the young people.
To catch the big fish, We also will need a small fish. Save the old people and you can reach the young ones, save the young ones and you will reach the old ones. The parents will see the change in their children and will become curious. If you are looking for Center Members, begin by serving the old people. I'm sure those who can persevere in this point will eventually succeed.