When something resonates strongly with us, and we find deeper meaning in it, this is called passion. Simply being interested in, or even really excited about something is not the same as passion.
True passion is measured in dedication. When we are truly dedicated and devoted to something, we consistently progress in that endeavor. We are not just there when the mood hits us, and we don't push it aside when times get tough. That's what distinguishes hobby from passion. No matter what is going on in the other facets of our lives, our passion drives us to study and progress in the development of this passion. Passion is the constant when everything is in turmoil, and if we are truly passionate about something, nothing in life is strong enough to distract from that devotion. The people who have a strong passion for something are immovable in their devotion to that cause or practice, and passion is a central characteristic in all arts. Passion leads us in the direction of taking the first step, and keeps us moving, leading us deeper and deeper as we progress.
A hobby is something that you enjoy and pick up when you have some extra time on your hands, whereas a passion is something that you adopt as a central ongoing development that stays with you throughout your life.
Passion is a beautiful thing, and having such a strong devotion to something makes us stronger when it comes to enduring hardships. Even if you are going through a very challenging season in your life, your passion remains your rock, your practice remains, and you continue to see progress.
This article was inspired by the words of Eriko Uehara Soke, one of my teachers and the 15th head of the lineage of Japanese swordsmanship called, "Hyoho Taisha-ryu". Uehara Soke wrote about this in the foreword for the book "Nakano Jinuemon Shumei's Unravelling the Cords" an annotated translation by Georgi Krastev, Alex Allera, and Yamamoto Takahiro Shihan. I found her words to resonate deeply with me.