Isabel Hickey said that Jupiter holds the secret to living life fully. Big J is at home in its own sign; therefore, the individual with Jupiter in Sagittarius has, I suppose, a fuller experience of this planet. Philosophical pursuits are explored and he/she likes to explore the answers to everything. In the psyche, there is an especially strong inclination to search for purpose, meaning, and significance in life. Growth is sought through a broader understanding of life as a whole. It is stimulated by travel, increased knowledge about other races, schools of thought, and nations other than their own.
The individual will find joy and faith through learning and have the opportunity in this lifetime to expand himself/herself through higher study, teaching, or foreign cultures. If Jupiter in Sagittarius is placed prominently in the chart, this may be a marker for the perpetual traveler of both body and mind. Yet it may also mean he/she is doubly restless, both on the physical and mental plane. One of their highest ideals is searching for the truth in all things and there is a need to look to the future.
Jupiter here may reflect the lifelong student; he/she likes to learn new things and there’s an abundance of enthusiasm. Moreover, the individual will have a fun attitude towards the Jupiter area. This placement of Jupiter needs to seek opportunities, and this position often denotes someone who has experienced some lucky strokes, especially if Venus or Uranus are involved in aspect. Often many opportunities magically appear, and it also relates to popularity, excitement, and adventure. The person benefits from traveling and further education; there is a lot of breadth in what can be pursued at the intellectual level.
Sagittarius energy is still fire, however, and no matter how mutable and flexible it may be, Sagittarius maintains its fundamentally one-pointed nature; and one of the best-known side-effects of this one-pointed nature is a tendency to operate in absolutes (not to mention a tendency to more than a little tactless). “Truth above all else” is Jupiter in Sagittarius’ motto, and this can often result in bruised feelings (and heated debates). Astrology: Understanding the Birth Chart
Jupiter in Sagittarius may have an interest in religion, sports, or a liking for the outdoors. The individual often has a proclivity for taking matters out of proportion, exaggerating, and being excessive, but this could mean being excessively generous. The type can be very sure of their ethical and moral principles and what he/she believes is right.