"To light a fire" typically means to ignite, start, or inspire something, usually referring to motivation, enthusiasm, or passion for a particular task or goal. Full definition
If that won't light a fire under your ass, nothing will! (fitnessandpower.com)
So light a fire in the fireplace, grab a blanket and your laptop and get comfy. (topresume.com)
We know that when it comes to growing the economy, alongside good infrastructure and great education we need to light the fires of enterprise. (totalpolitics.com)