1. Jupiter represents growth, and the freshwater of Cancer represents life as well as growth. Therefore, Jupiter feels most comfortable in the sign of Cancer and gets exalted here at 5%.
2. Cancer is the fourth sign of the zodiac which is ruled by the Moon. The fourth house also represents the mother’s womb. A pregnant woman is the best example of an exalted Jupiter in Cancer.
3. The unborn baby (fetus) growing in the womb floats in the fluid, indicating life expands in the water. Therefore, nothing should ever be done to harm a pregnant woman, otherwise Jupiter of such a person will be destroyed forever.
4. In ancient India, a guru's hermitage was always on the bank of a river. The students used to receive knowledge from their guru under the tree where fresh breeze blew. The expansion of knowledge near fresh water is another example of Jupiter exaltation in Cancer.
5. Jupiter gets debilitated in Capricorn at 5%; a sign ruled by Saturn. Capricorn is a sign of a high level of control, restrictions, and limitations. Therefore, the planet of expansion, feels completely hapless in this sign. The debilitated Jupiter in the horoscope shows that the person wants to do a lot in his life, but he has to face the problem of lack of resources.
Excerpts:- Jupiter: The Planet of Fortune