"Vayishma Yisro — Yisro hearkened" and he came. What did he hear? He heard what Hashem did to Egypt... Even though he knew that the Am Yisrael was the chosen nation, but what that meant he couldn’t appreciate until he heard of what had happened to Paroah...
Yisro was a gentile. But because of his ability to listen he was elevated and he is enthroned among the greatest in our history. — Repenting in Happiness (#17)