In other words we must become the substantial expression of God's personality. Father has always lived to become a man of God's personality, he endured great suffering to accomplish this. There is no other way to become true sons and daughters of God. God wants us to love the True Family, this means we should inherit their faith, their heart and love and their personality. However well we serve them, if we don't inherit these three qualities we don't really love them.
Many children say they love their parents, but follow a direction contrary to their wishes.
That's not love. On the other hand a child may not live with his parents or serve them, but if he fulfills their desire for him, he truly loves his parents. Our True Parents don't want us to serve them, they want us-to become like them, men and women of strong faith who embody God's personality, heart and love. That's what they really want. So we must try to have absolute faith in God.