Wise words, those are. We are conditioned as newly forming earthlings to take on the beliefs, attitudes and opinions of those raising us. It can even be considered a matter of disloyalty if we choose to reject them.
I came of age in the 1970s--hippies, pot-smoking, anti-war protests, women's lib. Along with long-term prejudices against African Americans, gays and Catholics, my parents had a lot of noisy, nasty opinions about all of them. As I moved through high school and college, I made friends with folks in all those groups. My inner voice told me that given my experience, those noisy opinions of my parents and older brothers just did not match the person I wanted to be. Along with multi-generation addiction, I elected to do my best not to pass ignorant prejudice onto the next generation. Like all of life, that's an ongoing practice.
It's an easy thing to let others' noisy opinions rule us. There is a huge element out there today with the belief that "if you don't believe like I do, there's something wrong with you." Too many people are much too ready to offer their opinions. One need look no further than Facebook to see that in spades. It takes courage to hear, trust, and use the inner voice alone.
Those noisy opinions change over time. Glancing at hippie photos on Google Images, I am reminded that the "evil drug" marijuana of the 1970s is now an accepted medicinal therapy for many aging hippies. Times change, thank God.
The inner voice is the source of peace. It can be trusted to never lead us astray.