Lyrics below in the description.

Recorded at the Music Men panel at BronyCon 2017.  This is a clip of the song We'll Make Our Mark from the episode Crusaders of the Lost Mark, with the missing Diamond Tiara verse that got cut due to time constraints.  The Diamond Tiara portion starts at 0:41.

Lyrics:

Cutie Mark Crusaders I've got, something I need to say
I was headed down a path that, was leading me astray
But now I've changed my ideas, you helped me see I care
I'm gonna show the world how much I have to share
You've made your mark, and showed me a better way
You've made your mark, helped me see how I could change
All I thought I ever knew, of my cutie mark