General Book of the Tarot, by A. E. Thierens, , at sacred-texts.com
"The walls indicate, that we are still in the visible, or material world." (P.) This relates to the picture which shows a child on horseback--or two children as in the older editions of the card--playing beneath the bright Sun and evidently within a walled enclosure. So far so good: we are and we remain in this world. And for the rest the Sun is the Sun and this card means everything that astrology can tell about the Sun, in every respect and on all planes. It means the positive or masculine elements in general, the power and function of will and concentration, great benefit and mighty protection in spiritual as well as in mundane life and matters. It may signify the father of the querent and high authorities, king, president, ruler, etc. The spiritual centre of man and the centre of importance in everything is indicated by it. Physically it indicates the heart and the solar-plexus.
The protecting power of the Sun is well illustrated
by "the hieroglyphic value of the Hebrew letter Quoph, which expresses a sharp weapon, everything that is useful to man, that defends him and makes an effort for him." (P.).
In a figure laid for divination this card indicates the centre of interest and that which is fixed, certain, assured and under protection.