What is inside of our heart according to the song lyric?

Read the song lyric below very carefully!

Hero

By Mariah Carey

There's a hero
If you look inside your heart
You don't have to be afraid
Of what you are
There's an answer
If you reach into your soul
And the sorrow that you know will melt away

And then a hero comes along
With the strength to carry on
And you cast your fears aside
And you know you can survive
So when you feel like hope is gone
Look inside you and be strong
And you'll finally see the truth
That a hero lies in you

Lord knows Dreams are hard to follow
But don't let anyone
Tear them away
Hold on, there will be tomorrow In time
You'll find the way

It's a long road
When you face the world alone
No one reaches out a hand
For you to hold
You can find love If you search within yourself
And the emptiness you felt
Will disappear

And then a hero comes along
With the strength to carry on
And you cast your fears aside
And you know you can survive
So when you feel like hope is gone
Look inside you and be strong
And you'll finally see the truth
That a hero lies in you
That a hero lies in you
That a hero lies in you

What is inside of our heart according to the song lyric?