The Mercury in Sagittarius Man or Woman
Job 36:11 - 12 "They perish for lack of knowledge" Anyone with their Mercury in Sagittarius would completely agree... Whether this divine knowledge is coming from God, Spirit, or even just a well educated mentor, the feeling will all be the same to this individual.
Here we have the expansive nature of Jupiter (the ruling planet of Sagittarius) combining with Mercury. In other words, a Mercury in Sagittarius Man or Woman speaks expansively and optimistically, always looking at the overarching truth about what is being said, and always tying their own statements into the same. Translation: good luck winning an argument with these people, because they are magicians at presenting something in a way which is connected to some sort of truth.
Unfortunately, this also means that the Sagittarius foot in mouth nature is heightened here, especially if this person's Sun is also in Sagittarius.
Talking about deep, dark emotions is where these brilliant thinkers and inventors really fall short because who has time for that when you are bringing truth to the world?
Sir Isaac Newton had his Mercury in Sagittarius (the image above is called "Newton's Discovery of the Refraction of Light" and it was painted by Pelagio Palagi) and so did Beethoven, and Marie Curie.
This connection to information from the Gods, seemingly, in many ways.
These people absolutely detest being told what to do, or being constrained or limited in their thinking and always stand by their beliefs regardless of what others say.
Mercury in Sagittarius is also very much concerned about life lessons for their own lives and making sure that they are experienced and communicated to others.
If you have your Mercury in Sagittarius, you may make an excellent inventor and in the very least you have a most brilliant way of thinking are are supposed to bring some sort of truth into this world.