As an "indicator of our soul" the Sun is the giver of life. The Sun also rules our father, our ego, popularity & honor in society, status, fame, heart, eyes, general vitality, respect, power and authority, especiallyt in top Government positions. So it no wonder that the Sun is strongest in one's 10th House - a house that denotes our career. He is also strong in the other squares & trines, viz. 1st., 4th., 5th., 7th., 9th..

In every person's chart the 3 houses - 3rd., 6th., & 11th are called growing houses - in other words planets in these houses get more pronounced as we grow old.
Example: Mars (a very belligerant/martial planet) in one's 6th. house of enemies may mean one will be bullied by the tough guys in school at a young age, but when himself grows up he will have the tremendous power to vanquish his own enemies.
The Sun does well in what are called the "Growing Houses".

On top of that the Sun is particularly beneficial for Aries, Leo & Sagittarius Ascendants. His nature is fiery, the metal is gold and his direction is East. His day of rulership obviously is Sunday, and he comes into full maturity and brilliance at the age of 22.