Testimonies Vol.  6, page 352 "But YHVH has set His Seal upon His Royal Requirement. Each sabbath institution   bears the name of its Author, an ineffaceable Mark that shows the authority of each. It is our work to lead the people to understand this. We are to show them that it is of vital consequence whether they bear the Mark of Elohim's Kingdom or the Mark of the kingdom of rebellion, for they acknowledge themselves subjects of the kingdom whose Mark they bear.

Below "both true and false" is added, which is not above.

 The Signs of the Times
Date - 03-22-10
The Sign of Loyalty
Paragraph - 13

The Sabbath question is to be the issue in the great final conflict, in
which all the world will act a part. Men have honored Satan's principles
above the principles that rule in the heavens. They have accepted the
spurious sabbath, which Satan has exalted as the sign of his authority. But
YHVH has set His seal upon His royal requirement. Each Sabbath institution,
both true and false, bears the name of its author, an ineffaceable mark that
shows the authority of each.