What is the authentic day Monday and what is its ruling planetary unit?

Answer from the V.M. Samael Aun Weor.

Monday is governed by the Moon; Tuesday by Mars; Wednesday by Mercury; Thursday by Jupiter; Friday by Venus; Saturday by Saturn; Sunday by the Sun. True order of the days of the week from a Cosmic and Magical point of view: After Saturday, which is the seventh day, comes Monday. MONDAY, WEDNESDAY, FRIDAY, SUNDAY, TUESDAY, THURSDAY, and SATURDAY. This is the authentic and legitimate Cosmic order.

Samael Aun Weor. Excerpt from the book: Treatise on Occult Medicine and Practical Magic.

Answer from the magazine "The The wisdom of the Being.".

Because the order of the days was changed in the Middle Ages, the authentic Monday is the current Sunday, and we are governed by both the Moon and Master Gabriel.

The Magazine "The Wisdom of Being" 105: "Monday."