(Cross posted from Your Readings as I think it's an reasonable introduction to I The Magician)
I The Magician is one of those cards which I have recently discovered a new way of looking at the card. I would argue that I The Magician is, next to The Fool, the most powerful card in the trumps; if not the entire deck. I The Magician can be related to The Thrice Great Hermes or Mercury (okay I'm using Alchemical terms here so you might want to check out the Alchemical Tarot Study Group thread dealing with I The Magician).
Mercury managed to learn, understand, and control the powerful Calderus (the staff with the two snakes wrapped around it). He is understood to be the most powerful magician there is--so there is your link to the power and strength.
Now I'm going to turn him on his head by introducing another side to him, the trickster. If you are currently settled then Mercury comes in to unsettle you--this is not a XVI Tower or XIII Death event--I rather think it's something a bit more subtle, an minor argument, feeling ill, reading a thought provoking article, meeting up with an old friend, making a new friend. Once unsettled you'll start learning and growing, and it is in this learning and growth that the second part of Mercury's power are visible.